Won't they fight?
Never had such a combo.
Re the truck, me thinks nephews should go to Grandma.
nephews = nephew
My animals never fought. They were usually quite good friends, and played a lot together. There are usually a few "display" acts, wherein, the one who has been here the longest lets the other one know who's in charge, but that happens with cats being introduced to other cats, and dogs being introduced to other dogs. It's called "the pecking order."