Be aware that most contracts in the dog world are not legally enforceable, especially the ones that are micromanaging. Legally, dogs are property. As a result, do not rely on contracts to ``force'' the behavior that you want. Instead....
Deposits are completely normal. Some breeders even ask for them in order to be put on the waitlist. They help the breeders to know who is serious and to know that the puppies definitely have a home.
So, many puppy contracts, or provisions of them, are not legally enforceable if they are unreasonable or micromanage the buyer.