NOTE: Horizontal Distance of FD refers to the length of the FD platform not the stage's entire horizontal space from left to right blast zone.
Angles are relative to the direction Link is facing when he hits the hydrant, so anything past 90 degrees means the hydrant will move in the direction behind Link.
Also, although it should be obvious the trajectories for the weaker moves only apply when the Hydrant is at the percent where the weak move will launch the hydrant.
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U-tilt: 95~ degree launch trajectory (roughly equivalent to the height of Link's FH), moving slightly backwards during the tumble.
F-tilt: 25~ degree launch trajectory, flying approximately 55% of the horizontal distance of FD before bouncing.
D-tilt: 85~ degree launch trajectory, flying high and forwards, good for cuttng off Pac-Man's jump and aerial options, bounces twice before disappearing and travels approximately 60% of the total horizontal distance of FD, 40% before landing and going into tumble.
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Jab 1: 95~ degree launch trajectory (Link's head in height), tumbling slightly backwards into Link's body.
Jab 2: 90 degree launch trajectory tumble, bouncing in place.
Jab 3: 25~ degree launch trajectory, flies approximately 60% across the horizontal distance of FD before landing, essentially the same trajectory as Swing 2 of D-Smash.
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EDIT 8/22/16: Some of the Dash Attack angles may have changed slightly since iirc Link's Dash Attack angles were adjusted in one of the patches that came after I originally wrote this up.
Dash Attack (Tipper): 45~ degree trajectory, flying 100% horizontal distance of FD, rises to approximately Link's FH height.
Dash Attack (Non-Tipper, Non-Hilt): 65~ degree trajectory, flying 100% horizontal distance of FD, rises to approximately Link's FH -> DJ height.
Dash Attack (Hilt): 85~ degree trajectory, flying >50%~ of FD's horizonta distance and rising to a height just above Link's FH -> DJ height.
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D-Smash (Swing 1 Hit; in front of Link): 50~ degree launch trajectory, tumbles forwards above Link's head and continues bouncing slowly forwards at around his torso height. Height of initial launch and following bounces depends on amount of charge for D-Smash and spacing (since a hit that connects at the Hilt will do more damage and knockback). Hydrant bounces 4 times and will travel approximately half the distance of FD regardless of charge (coming just short of center stage (when hit from the edge) uncharged and going just past center stage for high/full charge).
D-Smash (Swing 2 Hit; behind Link): 25~ degree launch trajectory, flies forwards about 90% of the horizontal distance of FD before bouncing and continuing forwards with a primarily horizontal tumble.
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U-Smash (Swing 1/2 Hit): 95~ degree launch trajectory, flies backwards slightly and just above Link's head before bouncing at around his body height while slowly continuing backwards, similar to trajectory of U-tilt.
U-Smash (Swing 3 Hit): 85~ degree launch trajectory, flies high and forwards about 60% the horizontal distance of FD, similar trajectory to D-tilt, bounces twice before disappearing, cuts off Pac-Man's jump and air options moving forwards but is slow to get rid of Hydrant such that Link will be pushed away before Swing 3 can connect unless Pac-Man is on top of the Hydrant such that the water will instead Pac-Man up.
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Arrows: 60~ degree launch trajectory, slight height and horizontal travel distance variation depending on charge of arrows, will travel about 90% of FD's horizontal distance if arrow is fully charged, will travel anywhere from 60-75% depending on arrow charge below a full charge. Bounces 4 times for all levels of charge.
Gale Boomerang: 80~ degree launch trajectory, a point-blank (7%) Boomerang will cause the Hydrant to fly high and approximately 50% of the horizontal distance of FD before landing, another good option for cutting off Pac-Man's aerial options. Hydrant significantly loses height at distances further than close range, 60~ launch trajectory, flying at just above Link's head in height and 25%~ the horizontal distance of FD before landing.
Bombs: 65~ degree launch trajectory, flying to a height just above Link's head before bouncing forwards at all ranges excluding point blank, will bounce forwards 4 times before disappearing when tumbling forwards. At point blank, a direct contact bomb (5%) will actually send the hydrant behind Link at roughly the same trajectory (EDIT 8/22/16: In hindsight I believe this is because the bomb will actually end up on the other side of the hydrant before it detonates if Link is standing right next to it, hence the backwards trajectory). Trajectory and travel distance are the same for splash damage bombs (8-9%), without the point-blank anomaly (of sending the hydrant backwards).
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An important note about launching the hydrant with the bomb's splash damage (8-9%):
When the Hydrant is launched by the splash damage hitbox, Link's "bomb ownership" (read: bombs will not damage Link if they explode in direct contact (5% hitbox) with an enemy or other object that isn't the ground when he is in the blast radius) does not apply, in other words Link can be hit by the hydrant if he launches it in this way. This contrasts from launching it with direct contact, in which case the Hydrant will not harm Link because the game recognizes that it was one of his attacks that launched it, a splash damage launch seems to register as an "unowned" hitbox and thus allows the Hydrant to hit either Link or Pac-Man as it tumbles.
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Spin Attack: 60~ degree launch trajectory, flying anywhere from 70-100% of FD's horizontal distance before landing depending on charge, will reach a height that is just above Link's FH jump height.
Nair: 30~ degree launch trajectory, flying 40-50%~ of the horizontal distance of FD depending on early or late contact (hard to get early contact before landing though), will bounce 2-4 times.
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Fair (Hit 1): 30~ degree launch trajectory, flying 40%~ of the horizontal distance of FD before tumbling, bounces 4 times before disappearing.
Fair (Hit 2): 30~ degree launch trajectory, flying 50%~ of the horizontal distance of FD before tumbling, bounces 4 times before disappearing.
EDIT 8/22/16: The distance traveled by the Fair hits may be further at this point since Link's Fair has been buffed since the time that I first wrote all of this up.
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Uair: 90~ degree launch trajectory, bouncing in place with potentially very slight movement forwards, impossible to hit ground Hydrant with Uair unless coming from beneath by the ledge.
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Dair (Meteor Hitbox): 270 degree launch trajectory (read: straight down), bouncing in place 4 times before disappearing.
EDIT 8/22/16: The original remark above was written before the angle change to the first few meteor frames of Link's Dair when it hit grounded opponents, I assume this angle change also applies to the hydrant so I will leave the original remark struck through until I or someone else can check the new angle and update the data.
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Dair (18% hitbox (just after Meteor hitbox): 50~ degree launch trajectory, flying at just above Link's height and 25%~ of FD's horizontal distance before tumbling.
Dair (15% hitbox): Same as 18% hitbox, travels slightly less horizontally than 18% hitbox.
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Bair (Hit 1): 50~ degree launch trajectory, flies low to just about Link's height before tumbling across the stage, bouncing 4 times before disappearing, flies <15% of FD's horizontal distance before tumbling.
Bair (Hit 2): 25~ degree launch trajectory, flies 75%~ of the horizontal distance of FD before bouncing, flies surprisingly fast as well.
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F-Smash (Hit 1; Non-tipper): 50~ degree launch trajectory, coming to Link's height and moving slightly forwards before tumbling, has some horizontal movement variation depending on Link's spacing for the swing when non-tippered, may tumble very short, may fly a bit further, etc.
F-Smash (Hit 1: Tipper): 40~ degree launch trajectory, flying low to about Link's height before tumbling, flies approximately 50% of FD's horizontal distance before tumbling.
F-Smash (Hit 2): 60~ degree launch trajectory, flying 100% of the horizontal distance of FD and reaching just about Link's DJ height at a maximum.