Big 12 is still after BYU, but it's unlikely they join in the near future. I think Rutgers will end up either in the Big 10 or ACC when all is said and done. UConn, as good as their basketball programs are, doesn't seem to be that attractive to the Big 12, probably because it's in New England. I would put my money on Louisville being a member of the Big 12 if they continue to expand. Cincinnati and USF have also been mentioned. If I was commissioner of the Big 12, I would take a look at Colorado State too since they lost that market when Colorado went to the Pac 12. Colorado's population is still growing. USF would be a larger market and helps the Big 12's recruiting efforts in Florida, but USF is just the 4th most (maybe 5th?) followed college program in the state. Cincinnati would put another team in the Ohio Valley and connect Louisville and West Virginia, but the Big 12 is concerned about UC's football stadium capacity, even though they could move "bigger" games to the Bengal's stadium. I'm sure Lousiville and WVU will campaign hard to get Cincinnati as the 12th member.
Baylor/KSU/KU stadiums seat 50k... Cincy at 35k. Wow, didn't know that stadium was that small. Then again, a full 35k stadium trumps an empty 50k one any day for my $. And they won't move games to Bungle Stadium if I had to guess simply because (a) not sure NFL likes teams having multiple games back to back at stadiums and (b) gotta sell out Cincy stadium first which probably won't happen that often - long way for folks to travel to see game versus Cincy.
Lewisville to B12 simply because they're a warm body close to footprint - probably their best alternative.
Cincy to B12 simply because they'll be a filler school for the NE div.
SUNJ won't go B10 imo - they might (big might) fit academically but their athletics program is a mess. They'll be ACC.
Co St won't be B12 unless they are desperate.
USF won't be B12 - no school really recruits outside of home state and adjacent states. TX/OK schools don't need FL and FL is too far away from other midwest schools to make meaningful recruiting grounds.