I honestly think that you should go and check it out with your own eyes and ears. You are going to be the one making a purchase from this breeder or any other breeder for that matter. You need to feel comfortable and happy with 'any' purchase of a Yorkie you make. You will be the Mother and Caretaker, so YOU need to feel comfortable with what ever decision you make.
Honestly, $100 is a great deal, and I would at least want to check it out. Of course if it all felt right to me than I would be taking the 2 of them home. I just feel everyone deserves to have a friend and playmate.
Also, I would ask for a 'longer' period of time for the guarantee. You might want to check out what the laws are for your state, they may very well be for 1 year.
Anyway, best of luck and let us know what happens
