Brawl/Melee Falco ideas [I'm writing as though you're taking the ideas, but feel free to ignore it - I also assume "unchanged" means unchanged from Brawl]:
Jab - frame one or frame 2, should be at least Brawl speed. Jab combo should be Brawl-looking.
Ftilt - whatever, this move is fine in all its forms
utilt - keep Brawl one, a bit of extra IASI frames might not hurt it but Brawl's might be better than I give it credit for.
Dtilt - PM one is better but if it's too good Brawl one is passable I guess
nair- PM nair is just fine
fair - make it Brawl's nair - good carrier move despite range and SHFFLing it can set up a jab or shine - should probably do about 15% if it all connects (4-3-3-5?). Low shield-stun though, because this would be waaay too good on shield otherwise though.
bair - whatever is fine, both bairs are good - leave PM's?
uair - PM uair I guess? I don't really know
dair - Sweetspot is a spike, giving possibility for shine combos (but very precise of course), the late dair has higher BKB to reduce punishment for a connection but a whiff - also makes it a decent edgeguarding move (maybe knock a few points off of KBG). Or just leave PM dair if that's what you meant by unchanged, but that's really good in conjunction with Melee shine of course.
Fall speed - if you alter the dair it should be Brawl fallspeed, if PM dair, it COULD be PM fall speeds but I think Brawl fallspeeds might in theory fit this Falco more - you could also make it a bit faster than Brawl, but slower than PM (maybe Brawl Wolf or Dedede's fallspeed? I've read those are a little more than half as fast as Melee Falco's fallspeed)
Lasers - I like Brawl lasers and SHDL which is why I suggested a more Brawl fall speed. But any of his lasers are good
Side+B - Brawl Phantasm - better distance I believe, so should use that
Usmash - Brawl usmash [pretty sure it's stronger than Melee's]
Fsmash - PM fsmash - Brawl's isn't as good but can use that too
Dsmash - PM dsmash, but lower KBG - his other smashes are much better
All throws but dthrow - whatever, PM or Brawl is fine
Dthrow - much more like Brawl dthrow, but with more BKB to compensate the increased gravity - shouldn't necessarily CG but should probably set up for dair or fair followups if one is fast enough (at least a laser or two, unless they DI up and that's high enough to avoid lasers). KB that's more vertical than horizontal (like 60 degrees above horizontal). Could also be designed to be exactly like Brawl Dthrow, but that seems a bit too good.
These are my somewhat more interesting [crazy] ideas
Fire-Bird - about 1.2X as long as Firefox - he's a bird after all, and PM has generally stronger recoveries - add Brawl's fire hitboxes
Shine - Melee shine (add the invincibility frame back[???]), if you hit A while Falco is in shine he'll kick it like Brawl in the direction he's facing - if you're holding B when it gets back, stay in shine or else it ends, and can JC it on the way back [once it has started to go back to Falco].
DJ height slightly decreased (about 0.7X as high?) [only makes sense if you read the next line]
Jump added [he's a bird] (this is why I figured dair would be much more Brawl-like, or the edgeguards would be too good - also should explain why I'd figured Brawl-esque fall-speeds).
So yeah. If any or all of it sounds good, I'd love to hear about it (or if it's all trash, feel free to say so).