BYU and Army could help the expanded AAC get P6-level bowl games and matchups. I would leave the G5 thing behind and create a New Year's bowl game for the champion with BYU and Army eligible for that bowl game in x number of years.

BYU or Army could be selected for any expanded AAC bowl game as long as within one game of the next available AAC team. (ie, if 10-2 Memphis is the best AAC team on the board for a given bowl selection, 9-3 BYU or Army could be selected - this is similar to the ACC's bowl arrangement with Notre Dame). Here's what I think the expanded AAC plus BYU/Army could do:

NY7 Liberty (Memphis, TN) v. NY7
Holiday (San Diego, CA) v. PAC
Military (Annapolis, MD) v. ACC/B1G/ND
Guaranteed Rate (Phoenix, AZ) v. B12/B1G
First Responder (Dallas, TX) v. B12/B1G
Gasparilla (Tampa, FL) v. ACC/SEC
Hawaii (Honolulu, HI) v. MWC
Cure Bowl (Orlando, FL) v. Sun Belt/CUSA/MAC
Frisco (Frisco, TX) v. CUSA/MAC/Sun Belt/MWC
Famous Idaho Potato (Boise, ID) v. MWC/CUSA/MAC