Good luck with that exit fee. They also need at least 2 more to have the minimum of 8 full members. Surprised UNLV (30k enrollment, basketball history, good market) wasn’t on their list of initial candidates. Last spot for 8 is a toss up between Utah State (geographical bridge to CSU 25k+ enrollment) and San Jose State (major metro 30k+ enrollment).
I’d take all of the above and try to add a Texas school like UNT or Texas State to recreate the Texas connection like they had with TCU. That gets you 10 teams for a 9 game round robin schedule leaving 3 OOC games, one for your P4 payday game, one for a G5 home and home, and the last for an FCS cupcake.
Other schools: Hawaii is a pain in the ass for travel, New Mexico sucks at sports, Wyoming is tiny (10k enrollment), no one seems to like Reno, and Air Force is a wild card that could be good or could be a head ache.
If this goes through look for the MWC to invite UTEP and NMSU from CUSA, Southern Utah and possibly non fb Utah Valley from the WAC to stabilize before turning their gaze at possible FCS upgrades from the Big Sky.