I've been working on this for a very long time, started a long time ago and got postponed for bits of time here and there. Many questions remain, and a few parts are missing. At any rate, the time has come for this data to be made available to all, both for use and for filling in the games.

Minus guys should love this.
Special thanks to Dantarion for Tabuu! (You'll need it to index any of this data for editing in your favorite hex editor.)
Code:
#Peach
Final Smash
1.0 Unknown, read 3 times at startup
1.0 Unknown, read 3 times at startup
10.0 Unknown
0?
0?
0?
13
8
Parasol
0.625 Involves input window to directionalize launch (larger = harder)
18.0 Amount to which the launch may be directionalized (larger = significantly more horizontal control)
0.95 Launch Height
0.6666 Unknown, read 1-3 times per frame during launch
0.5 Unknown, read twice on aerial launch
1.2 Floating Horizontal acceleration
0.3 Floating Fall speed
0.6 Falling max horizontal speed
30.0 Landing lag from falling state (frames?)
0? Unknown, never read?
Turnip Pull
80 Odds of getting an item (1 = always)
Toad
2.0 Horizontal braking speed (Peach continues moving horizontally at her previous speed divided by this constant.)
0.0025 Horizontal braking acceleration?
0.7 Vertical speed
0.025 Gravity
0.7 Max fall speed
13 Hitlag on hit (frames)
Peach Bomber
0.1 Unknown, read once on ground pullback
0.025 Unknown, read once on ground pullback
0.7 Unknown, read twice on ground pullback
1.1 Vertical boost during aerial pullback
4.0 Ground launch distance
5.0 Aerial launch distance
0.5 Post-launch vertical boost
0.08 Post-launch gravity
1.5 Some sort of transition ratio between post-launch and ending gravities? (higher = more of the second?)
0.1 Ending horizontal deceleration
0.08 Ending gravity
-1.2 Unknown, read on hit, controls direction of recoil
1.4 Recoil vertical boost
2.0 Unknown, something to do with ending
2.0 Unknown, something to do with ending, when set low causes massive fall speed, when set high casues momentary floating
0? Unknown, never read?
Turnip Table
6 Bom-omb ID
2.0 Relative odds of getting a Bom-omb
13 Mr. Saturn ID
3.0 Relative odds of getting a Mr. Saturn
4 Beam Sword ID
1.0 Relative odds of getting a Beam Sword
Float
150 Float time (frames)
#Diddy
Rocket Barrel
8 Unknown, read once on stage collision
1.3 Projectile Rocket Barrel flight speed
0.015 Projectile Rocket Barrel acceleration?
40 Unknown, projectile rocket barrel reads every few frames
10 Unknown, projectile rocket barrel reads every few frames
0? Unknown, projectile rocket barrel reads frame, sometimes twice
6.0 Unknown, projectile rocket barrel reads frame, sometimes twice
4.0 Unknown, projectile rocket barrel reads frame, sometimes twice
0.1 Unknown, projectile rocket barrel reads frame, sometimes more
1.5
0.1
0.1
10 Unknown, projectile rocket barrel reads frame, sometimes more
0.8 Unknown, never read?
0.02 Unknown, never read?
0?
Explosion
10 Unknown, reads on Final smash shots
Peanuts
0.2 Odds of final smash spawning nuts
4 Max number of nuts to spawn at once
48.0 Nut rotation speed
5 Frames nut graphic remains after hit
#Ganondorf
Explosion
1.0 Flame Choke Grab Slide
0.05 Aerial flame choke miss gravity
3.18 Aerial flame choke miss gravity related
20.0 Landing lag (frames)
0.1 Unknown, involves movement on aerial grab
1.0 Unknown, involves movement on aerial grab
1.0 Grab Plummet Speed ratio
5.0 Grab Plummet acceleration ratio
Kick
0.75 Speed modifier on hit
4 Unknown; reads on startup and at start of ground-ground ending
0.58 Ground-ground ending lag modifier
1.0 Aerial-landing lag modifier
0.5 unknown, Aerial-landing related
3.0 unknown, never read?
Warlock Punch
0.125 unknown, aerial release
0.7 unknown, aerial release
45.0 unknown, aerial release
0.8 directionalized release movement
0.92 directionalized release movement, vertical only
0? unknown, never read?
Dark Dive
0.0 unknown, cannot control if negative
0.5 leaping horizontal acceleration ratio
0.72 falling horizontal max speed ratio
30.0 unknown, read once on leap
5.0 unknown, read once on leap
8.0 unknown, read once on leap
0.225 unknown, read once on leap
0.33 post-release gravity ratio
#Popo (Ice Climbers)
Final
60.0 Unknown
SpecialHiPartner
SpecialHi
70.0 Max distance apart to trigger group up-b
1.3 Unknown, never read?
25.0 Unknown, never read?
0.25 Unknown, read on a couple of opening pre-jump frames
2.0 pre-jump horizontal braking (higher, more decelleration)
2.0 pre-jump vertical braking (higher, more decelleration)
-0.03 pre-jump vertical boost? (windup, goes down)
0.5 unknown, read one pre-jump
1.2 bonus height from nana
15.0 bonus height from nana inverse ratio (higher = less jump)
-0.1 fall speed modifier of nana throw
5.0
1.7
1.7
-3.0
5.0
6.0
-5.0
-10.0
1.9
-0.1
1.5
#Meta Knight
SpecialDown
0.5 Horizontal boost
0.4 Vertical boost
0.5 Horizontal acceleration
2.5 also horizontal acceleration?
0.5 vertical accelr
2.5 also vertical accel?
Tornado
1.0 unknown, read 3 times on startup
0.7 unknown, read 3 times on startup
80.0 minimum number of frames to stay in nado
0.12
2.0
0.1 horizontal acceleration
1.7 horizontal speed, has a cap
0.008 horizontal braking acceleration?
-0.08 gravity modifier
0.5 fall speed
1.0 vertical acceleration boost on b press?
10 related to button input--harder higher
1.1 button press boost vertical acceleration?
16.0 related to timing
80.0 minimum number of frames to stay in nado
1.5
70
2.0
10.0
0?
#King Dedede
Star Missile
4.0 Launch speed
0.13 launch decelleration
15.0 Star Spin speed
1.0
-1.0 Vertical displacement on launch
1.0
Jet Hammer
0.5 Walking speed ratio
120 time needed for full charge (frames)
Super Jump
1.0 Horizontal boost on startup
-0.5 vertical aerial boost on startup
-0.03 gravity boost on startup
1.0 Horizontal movement ratio
7.5 Launch vertical velocity
0.25 bonus gravity
0.9 Launch vertical velocity
0.3 Launch vertical velocity
17 Launch vertical velocity
24 unknown read once on landing
7.0 right star horizontal speed
2.0 right star vertical speed
-7.0 left star horizontal speed
2.0 left star vertical speed
WdThrow
1.9 Base throw speed
1.2 Strong throw ratio
18.0 Deafult Throw angle
12.0 Downward angle
26.0 upward angle
2 max number on screen
35.0 relative odds of throwing a waddle dee
10.0 relative odds of throwing a waddle doo
4.0 relative odds of throwing a gordo
3.0 relative odds of throwing a capsule
1 unknown, read on throw
1.0 unknown, read on throw
#Olimar
F-smash
4.0 Horizontal displacement
0.0 Vertical displacement
PluckParamTable
***SEE SAVED EXCEL FILE***
#Captain Falcon
#Jigglypuff
Final Smash
17.0 Size multiplier
300.0 Grow Time (Frames)
70.0 Scream Time (Frames)
100.0 Deflate Time (Frames) Interrupts at 120, retains current size
Rollout
90 Length of Rollout
20
0.07 Rolling Gravity
1.3 Rolling Fall Speed
0.1
0.05
6.0 Slows ground speed when lowered
16.0 Slows ground speed when lowered
0.08
0.1 Aerial horizontal control acceleration
0.5 Min Aerial Horizontal speed
1.0
2.0
0.5
4.0 Rotation Animation speed while pivoting or after hit
8
6.5
0.4
0.8
2.0 Bonus Damage: +3x to fast
3.0 Damage Multiplier: (4% base for fast)
-0.13 Horizontal recoil on hit
1.6 Vertical recoil on hit
0.6 Horizontal ending slide speed
0.8
1.2 Rolling Animation speed
32
50.0 Initial roll power (min 40.0--see friction)
180.0 Max roll power (min 40.0--see friction)
3.0 Roll power saved per frame
0.21 Initial charge animation speed
20.0
0.0 Increasing it cuts short distance traveled. Friction related?
40.0 Friction. (Subtracted from roll speed)
1.3 aerial rolling animation speed
0.03 Somehow linearly affects roll speed. Affects aerial speed more.
0.9 Pivot acceleration
0.2 Degree of influce slopes have on speed
2.0 Minimum speed required for sparkle graphics
0.25
0.75 Rebound speed multiplier
30.0 Length of post-recoil landing animation
Pound
0.1 Something to do with window to directionalize; when set high, can't angle
0.5 Something to do with window to directionalize; when set high or low, can't angle
20.0 modification angle
0.25 (aerial only, otherwise no idea)
0.2 (aerial only, otherwise no idea)
2.2 Aerial distance
0.92 Aerial decay rate (1.0 is zero deceleration)
0.0 (aerial only, otherwise no idea)
#Marth
Dolphin Slash
0.4 Max horizontal air movement in helpless falling (may transition to automatically)
34.0 Landing lag (frames)
0.25 unknown, read several times pre-jump
0.5 unknown, read throughout entire move
20.0 directionalization distance (displacement, not angle)
0.6666 directionalized pre-jump displacement (has a low max)
1.1 aerial jump height ratio (relative to ground version)
0.06 post-jump gravity
1.8 post jump max fall speed
0? unknown, read once post-jump
Counter Shield
all fully unknown
Counter
0.5 Aerial Horizontal momentum ratio
0.0025 unknown
0.04 Counter Gravity
1.2 Counter max fall speed
1.1 Damage Multiplier
0.9 unknown, read on activation
16 Frames of hitlag
8.0 min damage
999.0 max damage
25.0 unknown, read on activation
Shield Breaker
2 Charge time (seconds?)
8 base damage
5 damage per second of charge
0.8 aerial Horizontal momentum ratio
0.02 aerial horizontal deceleration
0? unknown, read once on initial pullback
Dancing Blade
0.5 Aerial Horizontal momentum ratio
0.0025 unknown, read once on first aerial startup
1.4 aerial vertical boost
0.072 unknown, read once on first aerial startup
2.0
0?
#Ike
Aether
0.9 aerial jump height ratio (relative to ground version)
8.0 unknown, read once on startup and jump
0.2 unknown, read once on startup and jump
5 unknown, read once on sword regrab
Counter
0.5 Aerial Horizontal momentum ratio
0.0025 unknown
0.04 Counter Gravity
1.2 Counter max fall speed
1.2 Damage Multiplier
1.0 unknown, read on activation
16 Frames of hitlag
10.0 min damage
999.0 max damage
30.0 unknown, read on activation
Eruption
7 max charge time (seconds)
10 base damage
4 damage per second of charge
0.8 aerial Horizontal momentum ratio
0.02 aerial horizontal deceleration
10.0 unknown
Quick Draw
70 Max charge time, damage (frames)
70 Max charge time, distance (frames)
4.2 Base ground speed
3.6 Base aerial speed
0.06 Charged ground speed (per frame)
0.04 Charged aerial speed (per frame)
0.1 Ground braking speed
0.065 Aerial braking speed
12 Travel time (frames)
0.5 unknown, read once on hit
0.3 unknown, read once on hit
0.1 unknown, read once on hit and ground stop
0.25 unknown, read once on hit and ground stop
0.5 aerial ending horizontal momentum ratio
1.0 falling startup boost
9.0 unknown, read twice on startup
-3.0 unknown, read twice on startup
9.0 unknown, read once on startup
#Snake
C4
-0.5 unknown, read on aerial drop
0.07 read twice on level load
2.0 read twice on level load
900.0 vvvvv
120.0 difference is time C4 stays stuck on target
1.0 unknown, read when C4 stuck to player
64.0 unknown, read when C4 stuck to player
1600.0 C4 lifetime
6.0 inverse probability of C4 being a butterfly
2.0 unknown, read once on surface set
1.5 unknown, read once on surface set
0?
Cipher
1.0 unknown, read on startup
0.05 min startup vertical velocity
0.25 max vertical velocity
1.5 unknown, read twice on startup
0.001 bonus horizontal acceleration
1.0 bonus horizontal max speed?
1.5 horizontal max speed?
9.0 unknown, read twice on startup
8.0 unknown, read twice on startup; cipher auto disappears if < 1.5
0.0 released cipher bonus vertical velocity
0.05 released cipher gravity (reverse)
3.5 released cipher bonus horizontal velocity
600 released cipher lifespan
10.0 unknown, constantly read while cipher is in use
Mine
-1.5 mine graphic/trigger vertical displacement
1500 mine lifespan
-0.5 unknown, read after planting is finished
-0.07 unknown, never read?
2.0 unknown, never read?
0?
Nikita Missile
0.0 Initial velocity
0.055 Acceleration
1.6 Max velocity
0.4 Max velocity while turning
3.0 angular speed
15.0 unknown, read twice on launch
5.0 unknown, read twice on launch
2.0
2.0
10.0
45.0
200 missile control lifespan
50 missile control lifespan (added, this can't be 0)
0.06 unknown, read twice on launch
20 unknown, read twice on launch (auto explodes if 0)
6.0
7
60
0.04
3.5
36
0?
Bullet (final smash)
28 Frame delay to hit
30.0 unknown, read constantly every shot
TrenchMortarBullet
0.0 Initial Horizontal displacement
8.0 Initial vertical displacement
0.0 Also Initial Horizontal displacement, but reversed?
300 Bullet lifespan
2.7 Base initial velocity
5.0 bonus initial velocity from full charge
0.1 unknown, read once on startup
2.0 unknown, read once on startup
30.0 unknown, read once on startup
0.5 unknown, read constantly
1.0 timing for projectile to rotate
10.0 unknown, never read?
10.0 unknown, never read?
-1.5 max/min horizontal speed of bullet
#Sonic
Spring Jump
3.0 Pre-jump frames (<1 makes spring invisible)
1.0 unknown, read twice on start
8.4 Jump vertical velocity
0.95 Aerial jump vertical velocity ratio
-1.0 Gravity ratio
6.0 related to jump height
0.5 apex horizontal control
0.65 unknown, read twice on jump
Down-b
25.0 Time spent in charge spin per press (frames)
25.0 Time spent in aerial charge state per press (frames)
60.0 Button press loop time
0.8 inversely proportial to time requirement of button presses
3.0 charge up graphic frequency
0.3 unknown (read constantly during charge)
6.0 unknown (unable to charge if set higher)
17.0 time allowed between button presses (frames?)
3 unknown, involves charge needed to attain "full"?
0.5 unknown (read on startup?)
1.0 unknown (read on release)
0? unknown (read on release)
Neutral b
0.8 ground startup vertical speed
0.6 aerial startup vertical speed
0.78 aerial horizontal speed decay rate
24 min charge time (frames)
40 max charge time (frames)
20.0 unknown, affects homing path
45.0 unknown (read twice on homing launch)
5.0 homing launch speed
3.0 homing target speed
0.15 unknown (read continuously at the end of the homing path)
2.0 unknown, affects angle change of path (read on homing launch and continuously at end of path)
15 time spent in move after a miss
0.5 non-homing stage bounce horizontal momentum ratio
0.25 non-homing stage bounce vertical momentum ratio
0.1 linearly related to non-homing stage bounce height
0.75 unknown (read on non-homing stage bounce)
3.8 target hit bounce height
3.2 inversely related to target hit bounce height (gravity related?)
10 inversely related to time spent in post-hit bounce speed
-50.0 non-homing angle
5.0 non-homing launch speed
7 non-homing time (frames?)
0.5 non-homing ending vertical braking
8 no homing braking time (frames?)
side-b
10 min charge time (frames)
40 max charge time (frames)
-0.3 charge horizontal speed
2.1 unknown, affects release launch speed (read once on startup and release)
0.065 unknown, affects release launch speed/acceleration (read once on release)
0.8
1.1
1.3
0.01
0.02
4.7
2.1
110
0.06
0.001
1.8
50.0
6.0
11.0
0.09
0.075
0.3
0.3
0.5
0.02
0.1
0.02
17
0.3
1.8
0.9
0.5

Minus guys should love this.
Special thanks to Dantarion for Tabuu! (You'll need it to index any of this data for editing in your favorite hex editor.)