[Belle Noir]

I don't think that is very accurate to say.
A recessive gene is a recessive gene, and in a closed gene pool, the chances of that recessive trait being expressed is much higher as the inbreeding gets tighter and tighter.
I'm not talking about the upfront pedigree, I'm talking 20-40 generations back, where you have the same dog names popping up over and over and over again, the further back you go.
Many people have no idea just how inbred dogs from closed registries are.

When you make a cross breeding to another breed that has the same recessive trait, the chances are no higher of that recessive being expressed than they are in pure breeding. If the other parent does NOT have a common occurrence of that recessive in that breed, then the chances are much smaller to none, in that F1 cross.

As for a Liger.
Lions and tigers are different SPECIES. Not breeds. I'm not sure your dog is the size he is for the exact same reason that ligers are the size they are. If it were, just as every time they breed a male lion to a female tiger to get a liger, and the result is these giant hybrid cats... every time they made the cross that produced your dog the dogs would be oversized as well.

But I will agree that every time you make an F1 cross of two disparate breeds, you have a huge range of conformation, coat, color, temperament, and other things that will express in the puppies.
IN GENERAL, though a yorkie-poo will probably have more curl to the coat and will be bigger... Though I'm not to sure about the less grooming part, lol.