Thank you for the update and additional info. Good that the mom of the pups is a good weight and that she keeps the pups to 12 weeks. I do not know the deal with chocolate Yorkies, they may be standard but IDK?? Does this off color come with any genetic defects too?
I am glad she has a year's health guarantee.
It is one thing getting a pup sight unseen from a well known and respected breeder, but more risky for a small hobby breeder with no history of many generations of litters.
Good luck and hope your baby turns out to be all you expected
By the way does she specify if you can breed her pups or does she require neutering as part of the sales contract?