Hi there, well I really don't know much about the coats of yorkies, but I can definitely say that the standard coat for a yorkie is suppose to be silky which is usually the finer coat, and some yorkies have more of a thick coat which can be very difficult to care for if you don't keep up with regular brushing.....I too had the same worries when I received my little Nemo all his other litter mates had thick coats of hair and his was just there, wild looking very thin would not stay in place for nothing....plus on top of that his coat grows slow....my friend bought one his brothers and her dog looks nothing like mine as far as coat her dog's coat is much thicker, and she has already had to have him shaved completely to the skin, because she was not caring for his coat properly ...on the other hand Nemo is now 6months and I bath and brush him regularly, and really don't have to brush him everyday and his coat just falls so nice from his head to his tail, it took a while after a bad haircut, but now it is starting to grow, and it is thicker than what it was when he was younger.....I could actually see his skin his coat was so thin even now on his ears his hair is kinda thin.....so just give it time as he gets older you will be able to tell how his coat is going to turn out.....believe me I was comparing Nemo's coat to other yorkies I'd seen on the internet wondering why his coat was so awfully thin, over time it did get better....
Wish you many happy days with Wylie....