I seen alot of stuff where people think we might get a triple fusion since he grabbed 3 of the bugs for that. So right off the bat you know it’s Goku/Vegeta but the question is, do they go with Piccolo or Shin. Until Shin actually got in on action and did some stuff, I 100% was sure it’s Big Green, but I’m not so sure about that now. I think we can get a swerve and they do Goku/Vegeta/Shin to really do something crazy.
As far as other theories go, I don’t really have any right now lol.