Precedent seems to indicate that the more over/accomplished you are in NXT, typically your main roster career will be the inverse of that, unless you have a decision maker (read: HHH) in your corner going to bat for you.
So, based on precedent? Aleister, Velveteen, Undisputed Era, Montez Ford, Bianca Belair, etc. ... dead in the water.
Kona Reeves? Absolute star on the main roster. Just give him the Rick Martel stimulus and fall back. The other guy in Street Profits that isn't Montez Ford? Multi-time IC champion.
Now for my honest opinion?
I'm worried about Velveteen. I feel like his gimmick is the type that works for the NXT crowd more than the main shows. Which is weird because from a sports entertainment POV ... he is as good as there is in NXT and maybe WWE as well. He's only 23 damn years old.
Aleister Black is basically Dark CM Punk with better strikes. He can definitely be something... on Smackdown.
Bianca Belair... should be a star. But she'd have to be a heel and away from Charlotte because that whole "superior athlete" schtick she has may cause a conflict. WWE will side with Charlotte on that. If she comes in as a face, go look at Asuka for her fate.
Ricochet could be the second coming of Rey Mysterio if they don't try to pigeon hole him.
Undisputed Era should be bulletproof.