I'm pretty sure we'll get a trailer sometime this weekend for Trunks, so he's def off the table.
Yeah Rhymestyle definitely hinted at something at the the end of the tournament.
So I'm guessing it's probably a trailer for Trunks most likely, I think we won't see anything until finals day probably.
There aren't a lot of prominent female Dragon Ball characters to choose from besides 18. Maybe they could do something for Chi Chi or Videl, and it's too soon for Caulifla or Kale.
True 18 is the only one I could picture getting in atm.