I think a 20/20 split will work the best, full round robin and a CCG between the two. Move UTEP to the MW and take Utah St, then add UNT and LA Tech or Temple to CUSA.
I think 10 per side would work best, too. But five leaving, they'd be down to 17. 8 MWC, 9 C-USA. They'd need three more.
I think you have to take FIU and FAU, because you need a Florida presence, which means UTEP would have to slide over, and only one slot would remain for the MWC.
I had 3, UNT Utah St and LA Tech(or Temple)
I think Dallas (or North Dallas) would be better than South Florida for recruiting and establishing a footprint, UNT and Tulsa go well together, moving UTEP over is a no brainer and pair them with New Mexico. The only major players left on the table in the West are Utah St, SJSU, and BYU; BYU isn't coming back, so the SLC market is very attractive so I think it would be BYU. SJSU has a decent market but its programs don't stack up (although they are improving) so unless UTEP refuses to move West they have little to no shot pending any state legislation or possible defection by SDSU.
So the MWC has 10 but loses 2 (BSU/AFA) and adds UTEP and Utah St to get to 10, and SJSU if SDSU gets a BE invite.
CUSA loses 3 to the Big East (SMU/UH/UCF) and 1 to the MWC (UTEP) so they'd be down to 8, UNT makes the most sense to add but that leaves 1 open spot. While theoretically getting back into Florida would be nice, I just don't see FAU/FIU as slam dunk options. With UCF and UTEP out the door I think CUSA would be smart to sure up its footprint. Marshall and ECU will be outliers of the conference and if UConn/Rutgers/Lville/Cinncy get lifelines to the ACC/B12 then they may be next in line to join the BE (more likely just ECU but both are options). In my opinion longtime CUSA outcast LA Tech would tighten the footprint and bolster the football strength and is the best option despite its lack of markets. The only other option should be Temple, if they get passed over by the BE again Temple and Marshall would make travel easier for non-fb sports and Temple has great bball which will only help CUSA in the long term. Consolidating CUSA's footprint can only work in its favor, there are more options available to them in the short and longterm in Gulf South TX/LA/MS/AL (UTSA/TX St/Lamar/SHSU/SFA/UTA/ULL/ULM/Troy/USA) and bordering states OK/AR/TN/KY (ORU/Ark St/UALR/UCA/MTSU/WKU) than in the Midwest (MAC), Northeast (UMass/Temple/Buffalo), or Atlantic.
While you could easily throw FIU/FAU in there I think like you, that you'd need both to really have a foothold in the region, and while UAB/Marshall/ECU may like that idea; I'm pretty sure Tulsa/Tulane/Rice/Memphis/So Miss would rather keep DFW in the fold over South Florida.
If CUSA decides against LA Tech again and goes for Temple I still think this could work well, if the Big East comes back for Temple/ECU/Memphis in the future then FAU/FIU could help stabilize the conference with the best or the SBC or the East wing of the WAC. Marshall becomes the biggest geographic torn in CUSA and could possibly be convinced to return to the MAC thus making both conferences more stable in the end I hope to see both CUSA and the MWC have 12 members and a CCG with some sort of BCS play-in game...something like this
MWC-Hawaii, Fresno, SJSU, UNLV, Nevada, Idaho, UtahSt, Wyoming, CSU, NewMexico, NMSU, UTEP
CUSA-Tulsa, UNT, TX St, UTSA, Rice, Tulane, LA Tech, So Miss, UAB, Troy, FAU, FIU
Fan of the Big 12 Conference, the Mountain West Conference and...