Speaking of AceStar, is that falling Nair into Elevator he tried to use the whole time true or not, or rage dependend or w/e?
It is true at any % actually because of weight based KB (but with rage the hits cause knockdown which means it can be teched), but he wasn't doing it quite right. A lot of the time he was getting first hit Nairs instead of the full falling Nair.
First hit Nair: combos best on fast fallers. Usually into Usmash/Utilt or UpB and possibly Dtilt/Dsmash on super fast fallers. On floaties you can get Usmash/Utilt only. Also sets up standing grabs and SH Kicks.
Falling Nair: Always combos into at least Dtilt/Dsmash/Utilt. Light and tall characters like Sheik and ZSS can be Usmashed in addition to those other moves
plus the Elevator. Heck, even Dash Attack works but it's hard to do and definitely not worth the trouble. For some reason this combo is really finicky on heavyweights, and occasionally fails if you try and UpB. In my experience, landing at least 3 hits of the Nair works the best. You can also grab them if you anticipate a shield.