Probably the best thing to do is establish a pecking order and stick with it - I think your dogs would be more comfortable knowing their place. It's worked out well in my house. My boyfriend and I got Spock in late July last year, then got Bones in early January of this year. Spock is older and was in our family first, so he always gets his food first, gets treats first, gets attention first, etc. Strictly enforcing the pecking order has helped out with Bones' dominance issues. They do play fight like little chainsaws still, but there isn't a real violence to it. Edit: And since your puppies are still youngish, they're going to be more rambunctious. Spock is 15 months old and has calmed down a lot, but Bones (13 months) has barely slowed down from when she first came to live with us.
A friend of mine had an elderly poodle (about 15 pounds), a bratty Yorkie (6 pounds), and a Great Pyr (100+ pounds), as well as a succession of foster dogs. In the pecking order, the elderly poodle came first, the Yorkie second, the Great Pyr third, and the foster dog was last. It kept the bratty one in line, kept the largest dog from feeling like he could potentially get away with harming the 2 smaller dogs (though he was the sweetest, gentlest, most loyal dog ever), and kept peace among the resident dogs when a foster came along, as well as taught the foster some discipline.
A friend of mine had an elderly poodle (about 15 pounds), a bratty Yorkie (6 pounds), and a Great Pyr (100+ pounds), as well as a succession of foster dogs. In the pecking order, the elderly poodle came first, the Yorkie second, the Great Pyr third, and the foster dog was last. It kept the bratty one in line, kept the largest dog from feeling like he could potentially get away with harming the 2 smaller dogs (though he was the sweetest, gentlest, most loyal dog ever), and kept peace among the resident dogs when a foster came along, as well as taught the foster some discipline.
