I feel compelled to chime in and support
Lady Jane's points. I don't know her personally, but have read enough of her posts to know that she has seen it all when it comes to rejected puppies, very ill puppies, and saving rescues. Her persistence in informing you is to only to help you become more knowledgeable and prevent the risk of getting a poorly bred puppy.
Key word is risk. You mentioned that
this puppy's momma is 5 lbs and you can only hope that the puppy is healthy. The thing is, all the high-risk issues Yorkies came from poor breeding. Heredity issues don't cut off - they are carried on from generation to generation. That's why the bloodline is really important. That's why no reputable breeder would 'pollute' their bloodline by breeding one that's too small.
Your Marie's 5 lb momma could have came from a 2.5lb parent or grandparent or great grand parent. By 'hoping and praying' your puppy will be healthy...well, then you're taking the risk by purchasing from an unethical breeder who has bred 2.5 lb Yorkies.
It's true any type of puppy can be a risk. BUT, if you take the time to find a good breeder, who has never bred their Yorkies under 5 lbs, that risk (in my opinion) is significantly reduced. At the very least, the breeder cares about the breed and not just the money. I mean, it's one thing to buy a puppy unknowingly. It's another thing to buy a puppy
knowing there's a higher risk, but just hoping for the best anyway...
At the end of the day, it's your obviously your choice.
I would take more time to find a good reputable breeder with zero red flags. Your puppy will be with you for many many years. What's another year to find a reputable breeder? To me, even if you have to go farther, it really is worth it in the long run. For me, I wouldn't limit myself to the choices of bad breeder, bad breeder, and not-as-bad-but-no-other-option breeder.
One last note (sorry for the lengthy response), most backyard breeders
love their dogs. Whether or not they're doing the right thing, that's a different story. So,
"family-raised" actually doesn't mean anything if they have poor breeding practices.