awwwwwwwwwwwwwwwww hes cute!! and I think he is 100% Yorkie!!! some yorkies have what is called cottony coat and thats what it looks like he has... as far as teacup theres no such thing... that is just how some BAD breeders like to make money...
but your baby looks like he will be a teapot! lol hes sooooooooooo cute! congrats!
eta: teapot is a yorkie thats big! there are a lot of them on here and they are ADORABLE!!!