Never been part of raising a mastiff, but St. Bernards are pretty close in many regards (drool included!).

Advice? Leash train him right now. While he's still littler than you. Be firm and consistent about NOT letting him pull. Walks will take longer right now if you stop walking and make him sit every time he pulls at the leash, but it will make the rest of his life MUCH easier to deal with.

Yes, I'm serious. Freckles (180+ pounds full grown) was leash-trained by the time she was three months old, and everyone remarked for the rest of her life what a pleasure it was to walk her. Same with Bruni.

Set other boundaries NOW, especially "all four paws belong on the ground!" Yes, he's a big enthusiastic puppy now, but 6 months from now he'll be able to knock over any unsuspecting adult with ease, never mind a year from now!

Don't know what size water bowls the girls have, but with that big ol' Mastiff head, same with block-headed Saints - my family always had a quart-sized mixing bowl on a big plastic placemat. Those floppy jowls WILL get water everywhere when he drinks, so the placemat is for your kitchen floor's sake. They are cheaper to replace than most flooring!

He may tend to bit a little on the stubborn side, and kind of a doofus (and I say that with all the love in my heart, no disrespect), but just be consistent and repetitive with his training, and he will (eventually) get it!

Oh, what a sweet, sweet face he's got. And is he Daddy's boy, or what!!! Angus must be wagging his whole back end up there at the Rainbow Bridge to see his daddy grin again. And it's hysterical that little blonde fluffball Honey is so "whatEVER" about him!

Oh, and keep a roll of paper towel in the car, handy for de-drooling people and things!