I am not sure barkbytes can be construed as an official reference. It also says until the 1930's Yorkies
usually weighed 30 pounds! I have some books with Champions through history and I think I would doubt that too. One little champion was less than 2 pounds in the early 1900's! They had over and under 5 pounds classes til 1960, and I read one from 1860's that had an over and under 9 pounds. Another topic, but it goes to credibility of the site you gave.
Your reference says Maltese were a possibility -- I guess anything is a possibility but since the Maltese is a spaniel, I am doubtful. I think I will go with the YTCA official position -- no white in the Yorkie history. For one thing the Maltese were dogs of culture and aristocracy -- I have a hard time imagining the weavers in the mills or the miners owning them. The Yorkie's were bred for ratting, after all.
You have to be careful about which references you use. It is officially recognized as a reference for the UKC or AKC? One of your references mentions Joan Gordon and Janet Bennett -- they wrote The Complete Yorkshire Terrier -- in which the history does not include Maltese. There is a quote that I like from that book, " some of our authorities have attempted to throw a great deal of mystery about the origin of the Yorkshire Terrier, where none really exists."
I have no doubt over the years people have sureptitiously bred maltese into the Yorkshire terrier lines.

But I am of the belief, that was not done before it was first shown in England or accepted into the AKC. But who really knows -- only the ghosts of a few old millers and miners, I guess.