COMPLETELY unrelated to Smash Bros (but related to Custom Robo), but I am planning on doing a large scale renovation of the Robopedia (assuming the people who moderate the Robopedia don't mind). I'm going to call it
Operation Robovation (if you guys have a better name, please let me know as Robovation sounds too corny). I have ordered Custom Robo (N64), Custom Robo V2, and Custom Robo GX as imports. They SHOULD come in within a month, but when they (as well as a video recording device) come in the mail, I plan on recording the effects of each gun, bomb, pod, action chip, leg, sub-weapon, and robo part so the Robopedia can be an encyclopedia of knowledge on how each part operates (besides just words). However, I lack the means of recording Arena footage, so I might need some help with recording on that front. If you wanna help with ANYTHING (whether it may be cleaning up articles, providing footage, pictures, photos, or other stuff CR related), feel free to visit the Custom Robo subreddit (or message me on Smash Boards).
Also, kinda got a good idea for the Zero Gravity FS that Zach777 thought of. Ray uses Soul Boost, equips himself with the AIRS parts (barring the Legs and Body parts), and activates the thrusters on his back (that's how Robos fly in GX). The controls are as follows:
A: ARS-G02 Beta Shot (Fires 5 shots that pause for a moment and then home in at a fast speed). Can move while doing move.
B: ARS-G02 Alpha Shot (Fires 6 shots in Rapid Fire). Cannot move while firing, but deals more damage.
X and Y: Rising Slide (Borrowed from Rising Chimera superboss in GX). Basically a long range tackle attack that deals great damage. LOTS of momentum though like Mega Charizard X's spinning tackle attack.
Automatic: Circulation W Gunners spin and fire in all directions while following Ray. Also the Force Protector protects Ray while not attacking. If Ray is hit by an attack without the field, he takes only 10% of what the attack would've done due to Soul Boost and suffers no knockback or flinch.
The FS lasts as long as a Soul Boost does in Arena.
So what is this guy's custom options? So you'll have a variety of ray models to choose from (I'm personally going to have a Ray Warrior). But what about his moves?
I'm thinking his specials are based on equipment. So for example.
B: Gun
F B: Bombs
D B: Pods
U B: Boots
So within each custom you'll have three of each to pick. For example
Guns
Dragon Gun: Long range slow moving fiery dragon head that everyone loves.
Needle Gun: Fires three shots at an angle and knocks opponents upward (Seems suitable in Smash)
Gatling: Great for spray and pray types.
Of course these are just example and I know a ton of other guns that would adapt well in Smash.
Boots will have to be a little different though. They can cause a special recovery (not featured in the game) but they can also affect his overall performance. So if you have ground boots he will fall much faster to the ground.
Now the real trick is can they also palette swap each item when you customize him?
I did something SIMILAR to your interpretation when it came down to custom moves. I however did the following for my specials:
Neutral: Guns
Sideways: Bombs
Down: Sub Weapons (specifically the Gunners as I use Pods in other parts of my moveset)
Up: Recovery (which cover a variety of topic areas)
For the Guns, I used the following:
Default: Dragon. It's so darn iconic [especially the sound effect]. But yeah, the slowest but most powerful of the 3. SLIGHT homing.
Custom 2: Sniper. Quick and deals decent damage, but always goes forward. No homing. The original hero used it in V2 during the Grand Battles.
Custom 3: Rayfall. Delays the 4 shots, but they have AMAZING homing capability. Decent speed though.
So, it breaks down like this:
Power: Dragon, then Sniper, then Rayfall.
Homing: Rayfall, then Dragon, then Sniper.
Speed: Sniper, then Rayfall, then Dragon.
For the Bombs, I used these 3:
Default: Geo Trap. The range is soooooo darn helpful.
Custom 2: Freeze. The stun is soooooo darn helpful (if you don't hit it yourself).
Custom 3: Gemini Bomb: Fires 2 bombs (one ahead and one behind of opponent). Might change this to Dual Bomb C though. I've seen good combo uses of it in Arena (it was a combo challenge in said game where hitting the front one bounced you into the back one where the back one either bounced you forward or upwards [I forget which way]). That and Ray used it in the V2 battle.
So, it's basically between Range, Stunning, and Restricting Movement.
For the Gunners, I used these 3:
Default: Round Gunner. Surrounds Ray and fires off shots. Sounds better on paper. Not really too OP in actual application.
Custom 2: 4-Way Gunner. Stationary gunner that fires a fan of shots forward. Kinda like a better version of the Killer Eye item.
Custom 3: Seeker Gunner. Stationary, but is always aimed towards an opponent. Pelts them with weak shots.
BTW, all 3 of them have a recharge time so they won't be over-used.
For the recoveries, I have the following:
Default: Acrobat Bomb. Self explanatory, but a bomb is launched point blank. The bomb does no damage, but it does deal knockback. You ALWAYS go up.
Custom 2: Robo Cannon. Fires Ray out in Cube form. Arcs like Rosalina's recovery, but it doesn't go as far as the Acrobat Bomb.
Custom 3: Short Slash Action Chip. Attacks opponent in any of the 8 directions. Goes slightly less far than Falco's Quick Fire custom, but deals great knockback and damage.
They're all different, but they get the job done.
Though I am intrigued about your leg parts idea. I only used them as aesthetics. Would it be that the recovery is the same for the 3 of them but the special effect after the recovery move is different for each move (i.e. Ground Legs make you fall faster but have lower landing lag overall, Formula legs boost your speed but have you have a hard time stopping, and Long Thrust makes your jumps longer but uncontrollable)?
Welcome to the Guild! 
