The problem with a C-USA/Sun Belt reshuffle is that Louisiana Tech categorically refuses to be in a conference with ULM, and will still try to dodge Louisiana (ULL) as well.
In all honesty, the best case is that the Big 12 goes to 14 with Memphis, Cincinnati, South Florida, and Central Florida. The American then grabs FAU, FIU, Western Kentucky, and Middle Tennessee. C-USA then stops at 10.
AAC West - Houston, SMU, Tulsa, Navy, Tulane, Middle Tennessee
AAC East - Connecticut, Temple, Western Kentucky, East Carolina, FAU, FIU
CUSA - UTEP, Rice, North Texas, UTSA, Louisiana Tech, Southern Miss, UAB, Marshall, Old Dominion, Charlotte
SBC - Texas State, Arkansas State, ULL, ULM, South Alabama, Troy, Georgia Southern, Georgia State, App State, Coastal Carolina
At that point you may be able to execute a swap - The Sun Belt adds Marshall, Old Dominion, and Charlotte in exchange for Texas State, Arkansas State, and either Louisiana or South Alabama:
CUSA - UTEP, Rice, North Texas, UTSA, Louisiana Tech, Texas State, Arkansas State, ULL/USA, Southern Miss, UAB,
SBC - ULM, USA/ULL, Troy, Georgia Southern, Georgia State, App State, Coastal Carolina, Charlotte, Marshall, Old Dominion