I think a lot of the multiple pup issues depend on the temperament of each dog.
We feed both Levi and our non-yorkie Dallas at the same time in the same place. Their bowls are next to each other in the kitchen, and they only eat the food we put in their bowl. No food aggression or any problems there.
We can't leave both pups out together we're gone because Dallas has severe separation anxiety when there are no humans around. Levi is perfectly fine and just sleeps...Dallas likes to destroy things.
So Levi gets free roam of the master bedroom and attached areas. Dallas is crated in the front bedroom, and acts like an angel while crated...go figure.