I've gone ahead and removed the 1other tag and ambiguous gender tags. We have over 900 posts by this artist spanning 14 years, but we have 0 examples of crossdressing or otoko no ko posts. I think that is enough evidence to warrant assuming a gender. If there were some examples of those, then I could see arguing the ambiguity, but if the artist has no record of having ambiguous posts then that should also serve as evidence of a lack of interest by the artist in drawing such posts.