I have a yorkie rescue, had for many years now, and he is the sweetest little baby.
I worked for Yorkshire Terrier National Rescue for many years, but hear good things about United Yorkie Rescue....
Have patience with the new baby....remember "dog's live in the moment" ..try to thing of him as a clean slate and teach him what it is you expect of him.
you may want a "belly band" if your baby is not housebroken

....We'll tell you where to get one if you need it

(or make one)...
roxanne