You have already pointed out one model that would work the 351BHT. I have the 09 Sierra 351BHT and love it! with the dual slides in the back you can sleep 6 just the the back with plenty of room to spare. She is very heavy though so you need at least a 1 ton TV. I pull with a 1 ton GMC Sierra dully diesel. Since your family is bigger then mine I think this is where you might have an issue. You might need to look at a used Ford Excursion diesel to be able to tow that much weight and also have room for the kids and pups.
Here is a pic of the rear bedroom:
Cant zoom out to get entire room. this is one side and the other is the exact same.
This is the entertainment center in the same room....
Hope this helps!