Hi Buster's Mommy and welcome!

He sure is a cutie and WOW, what a great souivener from Germany, doesn't get any better than that.
You are blessed to have had the ability to grow up with Yorkies, I am on my second Yorkie and will be the only breed for me till the day I die, I absolutely love the breed!!
You mentioned biting as he plays, well my only suggestion is to give him a command when he does bite and then ignore him for a bit. When he has calmed down and being good give him attention. If he begins to bite again, start the command and ignore training again. I have found that attention is what these Yorkies thrive on. Being ignored is not their favorite thing in the world. I am sure he will learn that biting is not an approved behavior in no time at all.
Thanks for sending the pictures, he is wonderful!!
I am loved by Schatzie who is almost 9 months, she is the sunshine of my days!!