http://www.hsvma.org/assets/pdfs/gui...-disorders.pdf
I am assuming that your friends do not know the lineage of either of the breeding pair in terms of health and did no pre breeding screening tests.
As you may or may not be aware the Yorkshire Terrier is I believe at risk for over 20 genetic diseases, and the Chinese Crested a half dozen or so. Breeding mixes does not guarantee in anyway you don't double up on the recessives. Or in other words have a dog with the best chance of good health.
The report above is easy to read and you can see for yourself what they all are.
It probably is a wise idea to secure as early as possible full insurance coverage for genetic diseases for this new pet.