I brought my Razzman home at 12wks and almost 2lbs. I never had to give him nutrical, he was a fine eater from the moment he walked into my home and heart
So it is great you are preparing yourself, but just have the nutrical on hand (in case it is needed).
I too own large dogs, and I had prepared a couple of safe places for Razz to sleep in, and to play in. I had a doggy play pen, and he slept in his crate beside my bed.
Closely supervise play inter-action with the big ones and your puppy.
Ideally your breeder will send you home with some of the food the puppy is used to eating, then you can gradually change him over to the kibble you want him on.
The library here has wonderfull articles on new puppy care.