I really don't recommend trying to force dogs to interact or decide who is dominant or who is submissive. In multi-dog households, their still has to be an heirarchy chain, with you at the top. How can you stay at the top of your pack?
-Teach your dogs "wait"--doors, gates, etc YOU should always exit/enter first, and the dogs second.
-You supply their resources, and that is a dominant position(food, shelter, etc).
-Call your dog to you to play or pet, rather that having your dog come to you and demand attention.
-Leash-train your dogs--a dog who pulls is leading the way, making you nothing more than a follower and even just baggage to drag around. If you don't know how to teach your dogs to walk beside you on/off-leash, feel free to ask or browse the forum. There are many posts on this.
There are many other things to help you stay the alpha of your pack, but these are the main things to remember.
Aside from that, I do not believe at all that you can change a dominant dog. It is in their nature to be dominant, and there is nothing wrong with that. AGGRESSION is an entirely different matter, although
uncontrolled dominance is often part of the problem. The more dominant dog will dominate the other dog--standing over him, putting the other dog in its place if it tries to do anything impolite, etc. This is okay--so long as the dominant dog is not going to give your submissive dog a complex and a vet bill. A dominant dog typically does not cause physical damage when they dominate another dog--two
very dominant dogs may have recurring tiffs, but 9 times out of 10 the food chain is sorted out and the more submissive dog knows who's in charge, so she'll respect the dominant one enough to not cause problems.
Your older dog may correct the puppy, no matter how dominant, if she tries to snoop in her food, take her toys, sleep in her bed, etc. Let her--puppy will either correct her or back down. These corrections(from either dog) are important in sorting out who's in charge. Let them just be dogs--your 8-wk-old puppy is not going to put your Pom-Chi in the vet. I also think it is not good at all that your pup has been quarantined with no human contact! The prime socialization period only lasts until 12 weeks--not that you can't socialize an older dog, you can and it is in fact important. But the best time for the majority of socialization is in the first 12 weeks of life, so she's missed out on 5 wks of a lot of socilization! You have a lot of catching up to do.
You don't really have to teach them to interact with each other, just let them. I really recommend crate training, as the puppy needs a place to get away from the stress of the new home. Older dog needs to have the alone time as well, so if pup is crate trained older dog can have some time without the playful pup.
Hope this helps, and if you have any questions feel free to ask! Welcome to the Academy, congrats on the new pup, and enjoy the site!