Welcome and congratulations on finally having your puppy dreams come true!!!
It's better to wait until close to a year to have him neutered so that they can pull out any remaining baby teeth at the same time. Yorkies tend to retain baby teeth and so end up with a double row of teeth - that can lead to tooth decay and bad breath - so they need to be pulled.
I can't think of any item that hasn't already been mentioned that you'll need right away. Just relax and enjoy your pup! They grow up too fast. Definitely check out the Health & Diet section for suggestions on food. Bottom line - don't feed him anything you would find in a grocery store. Good luck!