I don't disagree that her OCs can be similar to their PBs, but this seems to be a chronic issue with most PB-using OCs that I've seen.

Obviously the PB has to have a look and a set of facial expressions that fits the OC, and sometimes the best fit is a character with a similar personality or role. If you choose one that's very close then sure, it will fit well, but it makes the similarities between the two characters way more obvious, and also I know some players tweak their OC's personality to fit the given expressions. If the OC had hand-drawn or (dare I say it) face-maker icons or anything of the like, I think the similarities would be less apparent. (Unless your OC is named something like Prissy Guardian Sailor Dune).

tl;dr PBs can really suck and some players need to learn to handle them better. Or at least learn to go for really obscure characters.