Welcome to YT!
I agree - try to get his past medical records from the person you bought him from. I don't want to be a downer, but getting him cheap from Craigslist could give you problems later. It might not. I found Mandie on Craigslist before I found this forum. So far I have been lucky, but she was not from a reputable breeder that guarantees health and tests the parents..therefore she may end up having genetic issues later..as may yours. I don't want to scare you..just prepare you to be especially attentive to any changes in health or behavior.
Definitely get this little one to the vet for check up. And, keep nutrical on hand and research signs of hypoglycemia, ok?
I mainly wanted to say Welcome and ask any questions you have. We love all Yorkies and we are here for you
The last thing...about the cowering when going to pick up..Mandie still does this at 10 months old. I believe their size makes it especially scary to see a huge human bending over them
Do what I did from the time I got Mandie..it makes a difference...kneel down on the floor to the pup's level and then pick him up.