I think it may just be viewer's choice, unless you go to the pro/show level. The particular goldie in question would likely go into an "open" category, in a show, rather than a breed-specific category.
I know that breed crosses happen a lot, but when there's not a really dominant characteristic that can place it definitively (for example, I've seen an oranda/ryukin cross that was classified as an oranda because of its wen), it's kind of up in the air as to what exactly to call it. When a cross does have a dominant characteristic (such as a wen) which supercedes other characteristics in terms of classification, things become much easier. However, in this case, the fish's body does not appear to have that special pearlscale ball shape, which would, if it was apparent, place it firmly in the plain-old-pearlscale category.
Technically, I think either "pearlscale" or "pearlscale fantail" would be correct, given how predominant that particular scale type is in classification. The latter is kind of nice, because it provides additional information: you can tell without seeing a photo that it is not a tiku or hamanishiki, for example.