hmm, that wip 0.9 desyncs for me during pyslocks boss fight, what version are you using?
I think beast may be the fastest for the last level. The magneto fight takes up most of that time. With beast it's possible to hit magneto with jumping punch, normal punch, then both hits of his special move. I've always reguarded beast as the fastest damage dealer, mostly because of his two hit headbutt is the best finishing move, his normal punches also do good damage.
Things you might be able to improve on:
BEAST:
For the beast miniboss, it's faster to do down+y move near the middle of him. Then do mid air punch above him just barely hitting him, then down+y, mid air punch, and so on. Also you might to stick to the lower pipe right after doing down+y and you can immediately do the hanging punch, so you could alternate between down+y and hanging punch. Then you may want finish him off with mid air punch, normal punch, special attack.
Basically when doing the down+y for damage, you don’t want to go too high in the air, it wastes time, it’s better to start at the bottom then do them series of three.
When jumping over the brass knuckle guy, try to do it with the up+y move instead of having to wait for that explosive thing on the platform.
For the sentinel bosses, try doing this combo: jumping punch x3, normal punch x 2, special attack. You’d probably need to be behind them and have them not attack. If that doesn’t kill them, you could try throwing in either normal punch in the beginning, or down+y.
GAMBIT:
Near the begining, you can jump and get hit in the air from a gernade and be boost up to the platform your going to, or you can kill the first brown guy, then there will be a brown guy up there who can boost you up, sometimes there's a green guy on the boxes instead, I think he needs to do the jump attack to boost you up.
That barrel in the elevator chamber will kill everything after it explodes, save it for the last set of elevator guys.
When fighting the brass knuckle guy I think it's faster to not knock him down. Do your set of staff attacks, then either pause long enough, or do a duck attack or card toss to the opposite side, or do two jump attacks on him, then do another series of staff attacks. I think doing the jump attacks is faster.
Was doing up+y three times on the final boss faster than doing staff attack combos?
"Great spirits have always found violent opposition from mediocrities. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence."