Probably not, to be honest. I already entertained the idea of a Fanverse Mii costume, but it all really depends if Nintendo wants to go the extra mile or if they just want to stick to the FNaF universe itself. Plus, they'd have to get the rights from the fangame devs themselves.
Agreed... to an extent. We already have a jumpscare-like victory animation for Piranha Plant (with it initally being off-screen and then dropping down from above), and I think that'd work well enough for Freddy. However, I'm not sure how you'd incorporate a jumpscare in a victory animation without a warning period; If it happened right off the bat, whatever jumpscare scream you use will probably be mixed with the announcer declaring Freddy's victory. Maybe it could be a situation like Joker where the announcer is quiet, though.
Here's a (fairly unrealistic) compromise between the two ideas; All of Freddy's victory screens open in a black void, similarly to Sephiroth and his fire. After a second, Freddy leaves the shadows to do his victory pose, one of which could be a jumpscare. I think that mixes up the suspense of whether or not you'll get jumpscared and the warning period.
(While we're talking about Freddy's victory poses, I'd like to propose a victory
theme:
An excerpt of the unused "Showtime" song from Help Wanted. We hear it at the end of Security Breach's first trailer, so it's not farfetched to assume the song will make a reappearance in one way or another in that game.)
To be honest, the only animatronic who isn't another Freddy that would work is Bonnie (the two share very similar models in the first game). That said, I don't think any of the other animatronics should be alts (not even any of the other Freddys); Unless we made Freddy's moveset out of moves that the other animatronics could also use (which I'm not really a fan of), it'd just be kinda farfetched.
By the way, how many noms do I have right now?