Parti is full yorkie. Just not standard.
I have a Biewer (BTCA) and (AKC) yorkie "mix" but still full yorkie.
(Mom and Dad here
Our Puppies Cricket and Toby)
Jimmy has a little white on his chest still and he is 7 months.
I was reading that it's ok, even for breed standard AKC, that a small amount of white on the chest, is ok
Disqualifications:
American Kennel Club - Yorkshire Terrier Any solid color or combination of colors other than blue and tan as described above. Any white markings other than a small white spot on the forechest that does not exceed 1 inch at its longest dimension.