Madge, having re-read your OP - mostly to bleach the thought of BFY and Larry together in the hot tub from my mind - you really have literally nothing to lose. Your band can't move forward with these two guitarists. If you hurt their feelings and they stymie this band, well, this band is already stymied.
And if you behave like an upright person, their wives can't get cross with you.
My band used to jam for 2 hours every other week. We tightened that up to at least 2 hours (but usually 3) every week. Same time, same place every weekend. Not everybody can make it every weekend, but the rest of the band gets together and goes over stuff.
Regular rehearsals have (fancy that!) improved us no end, and expanded out repertoire, and our capabilities. We're all weekend warriors of varying experience and ability.
So get your rehearsals scheduled. As soon as it becomes apparent that one or more of the guitarists can't give enough time, ease them out. If they won't leave of their own volition, give them The Talk. Once you have regular rehearsals that they aren't attending, The Talk can be something along the lines of "Look, if I wasn't able to attend rehearsals, I'm sure you'd be looking for another drummer....so what would you do in my situation? I need a guitarist who can attend seshes."
I have some experience of tricksy guitarist departures, having had 2 family members in my band. One got pushed and the other (later and separately) jumped.