Putting myself into this situation, I would take two weapons and one son with me, our position would be outside perimeter on high ground with any cover we can find and a good zone of fire that would let us see approaching bad guys and within 100 yards of the home/shelter place. Son would be instructed to keep my .308 ammo full and ready to hand off, keep his head down, and only pick up the AR if bad guys are within 100 yards. Reasoning, I am the best trained and best shot, every shot needs to count, so no ammo would be wasted if I am doing the shooting and he is feeding me ammo. If my position is being overrun, then son picks up the AR and starts stinging them with lead, with me by his side to coach if he freezes up. The .308 can start engaging at 500 yards, the AR would be most effective as bad guys close in to 100 yards or less. If bad guys get past me and son and are between us and the house, I would take-over the AR from my son, and quit using the .308 because it could penetrate the house where wife and other son are holed up. Son is instructed to use these same tactics if I am hit and no longer in action.
Wife and other son remain in protected positions in house, making last stand in close range positions. Son busts intruders dumb enough to come through the door with the 12 gauge, because he can handle the recoil better than wifey. Wifey finishes 'em off with the .45.
Before engagement read Bible, say prayers.