Hi,
My pup is 5 months old now and from the moment I brought her home I have not let her bite us. When she is playing and she bites I sternly say "NO bite!" and move my hand. She catches on and stops eventually. It is very important that you don't send mixed messages. I know in the past I would play with puppies and they would bite and I thought it was o.k. because we were just playing, but the thing is the puppy doesn't know that sometimes it is o.k. and sometimes it is not. So, what I decided to do was to never make it o.k. to bite. She does really well, but always tries to see if she is now allowed to or not.
I like the idea of the spray bottle. That seems to work really well. Good luck!
Oh, my Sophia also does the same thing with the puppy pad. She will usually pee on it but does her poo in other places....mostly around the dining room table...yuck!!! The way I figure it is that Yorkies are just not good at house training and it is going to take a long time and maybe she is going to have to be much older before she really gets it. Lots of patience is needed I guess.