There's other ways to handle this. If you have a Yorkie rescue, or any other rescue nearby, plan the takeover with them. Make sure they have all the legal documents ready so it can be done in one visit so there's no chance of the 'breeder' making the litter disappear overnight. Be invisible when it goes down to prevent a backlash on you. If the laws are being broken then this will happen by the same 'breeder' again and again. This sounds like a take the money and run 'breeder'. You can help prevent it.
Another way is to find a surrogate to help with the weaning.
I worry that any pups not taken by deadline will go to a dumpster, so the rescue plan might be the better idea.