[Belle Noir]

This is a great post, and one I was looking for, as every one says make sure the breeder does health checks, and then aside from mentioning bile acid tests, says little to nothing more on it.
If I can add, there is a genetic test for PRA-prcd. This is Progressive Retinal Atrophy - progressive rod cone degeneration. This test determines if a dog is clear, carrier or affected. While an opthamologist can determine if the dogs have an eye condition for CERF, only a genetic test can determine if a dog carries it, or is genetically clear of this form of PRA, as a carrier will test the same way a clear will in any kind of eye exam.
Interestingly, Opti-gen recommends this test for yorkies, but Vetgen doesn't.

A good breeder should have his dogs CHICed at the minimum, which stands for Canine Health Information Center. However, just because a dog has been CHICed, doesn't mean that the dog is normal or healthy, since the dog can get a CHIC number after failing every test. All the CHIC number means is that the breeder has had that dog CERFed and OFA'd for Patellar Luxation, and released the results to the public. Doesn't mean the dog isn't going blind and can barely walk, so it's up to the buyer to take the time and look up the dogs CHIC number and see what the results are.
Also, and this bothers me... Other important tests are only OPTIONAL. I have no idea why bile acid testing would be considered optional... especially since as I understand it, it's the breed club that comes up with what they feel is required for CHIC within their breed. One would think that bile acid testing would be required, not optional, but there you go.
Other optional tests are OFA hips, OFA Legg-Calve-Perths, Autoimmune Thyroiditis, (if I am interpreting what I read correctly), and Cornell DNA. They do not mention OFA elbows, though randomly looking at some dogs pages, they will record the elbows if they're done, or any other type of thyroid testing should be done, and if so, what one(s).
They didn't mention elbows, but I have seen yorkies on the CHIC site with their elbows OFA'd.
Also recorded on the CHIC site is cardiac results should someone choose to get that done, though I don't know what the prevalence of heart disease in yorkies is, and so how necessary cardiac testing would be. Perhaps one of the breeders could chime in. This isn't even mentioned as an optional, but I have seen it recorded on different dogs pages, so it IS one that is recorded.
I believe this is done through a cardiac specialist, and through an echocardiogram, but someone else can correct me if I am wrong.

I had fun looking through vetgen's DNA tests, and one that popped up for yorkies is the DNA test for primary lens luxation. (PLL). I actually have not seen this mentioned on this site, but I also admit I have not specifically LOOKED for it. Nor have I seen it mentioned as a possible problem on reputable breeder sites.
I don't know if it means it's not something that anyone is looking for in the breed (but why then would there be a genetic test for it??) or if it's something that's rare, (but again, if so, why is there a genetic test for it??) or what the deal with that would be.
I am assuming that it's something like PRA, if it is present, it will be detected during a CERF, however, if it is something that is genetic, a dog that CERFs clear could still be a carrier.
It'd would be great if again, the breeders could chime in on this.

This is all I have been able to find. It may be way too long, but the more informed the better, one would think. For sure, all of these potential issues aren't going to be present in every dog, or in every line of dog. Some of these are far more important than others. The OP's post in order of relevancy is pretty good, I think.
I'm just tossing some other things out there based on what I was looking for, because again, puppy buyers are told to see what health tests the breeders have done on their dogs, but then don't really tell us what we should be looking for.

ETA:
OH!! How could I forget!! The greatest thing about CHIC is that if you're lucky, you can track back parents, grandparents, half sibs to grandparents, half sibs to parents and half sibs to your dog and see how the whole line is holding up genetically, or if any concern has popped up.
This is, of course, of the owners release the information, lol. But if they do, you get an even better idea of the genetic health of your dog and your dogs family, which is awesome I think.