Your pups are darling and I'm glad you have a great experience
With that said I don't understand the mix breeding and why people want them and pay the high price tag vs a purebred for the same price. With mixing I don't see how you can ever really know what traits you are going to get. Which parent will throw what trait? With Yorkies I would think people like the coats and with mixing you won't get that type of coat. Can I ask the OP what you didn't like about a purebred Yorkie that would make you buy a mix?
I am not putting down mixes at all just really don't understand. I can kind of get the labradoodles because of a medium size dog that might not shed ( not many to choose from) but on the smaller non -shed I don't get it.