Yes, the Yorkshire Terrier is a small dog, so having a small litter is common.
Yes, it will return to normal, although a little bit of sagging may remain.
That is not normal you should have that checked out!
For a while after having them yes, but will return to normal.
Toy dogs (Chihuahuas, Maltese and Yorkshire Terriers, and others under ten pounds) have a normal rate of 100 to 160 beats per minute.
its called corophagia. quite normal for puppies to do this. it is believed that they are lacking a protein found in feces
Yes it is normal for puppies to be play rough. Puppies have a lot of energy and they burn off that energy by playing. They don't mean to be rough, they're just having fun.
Staffordshire bull terriers do shed their hair, but it should not be too much shedding, if it is, there could be a problem and the dog should go to the vet.
No it is not normal for chihuahua to eat its puppies at birth
The number of pups will vary regardless -- but PLEASE do NOT cross-breed these dogs! Breeding is a serious venture and purebred lines should be respected for the best interest of the dogs and the breed. Poor breeding results in weaker dogs with more medical problems, and mutt pups are denied official recognition by many organizations and venues. In short, it isn't fair to the dogs in question, nor their respective bloodlines.
Feed her at normal feeding times and feed her a little more than usualy, after having puppies dogs get really hungry and it takes away alot of energy to feed the puppies.
Yes.
Yes, it is.