They'll all end up doing the same thing, and the G5s will follow along. BYU's options if schools go conference only will be to either play only independent and FCS schools (not including Notre Dame) or to join a conference for the year.
So if the schools go conference-only and BYU doesn't join the MWC or AAC (or Big 12 if you're lucky), then the schedule will probably look like this:
Army twice
NMSU twice
UCONN twice
UMASS twice
Liberty twice