These are all good observations, and "red flags" and all that, but you've got to let all that go... that was on YOU for not doing the research up front (instead of after the fact), so as bad as the breeder may have been, you were a worse buyer
But that's water under the bridge. Being a purebred buyer for the first time is confusing as heck, and it's a learning experience. If there is an next time, you'll do better, but those cats should be your focus now. Forget the breeder, you are done with them. Focus on the cats you have instead of worrying about the ones that you could have had. Don't compound your errors by now being a bad cat pet parent who is more worried about some sort of revenge against the breeder, that shouldn't be your concern anymore.
Sherry's advice is good. Start by finding a good vet (and now is a good time to use your improved researching skills), and just be honest with the vet. You bought these cats, you bought them from an irresponsible breeder, and you don't have records. Let them come up with a game plan with you as to how to go forward. Bad breeders can still produce good cats
Especially with the right pet parent.