There are a few case examples of artists with shared accounts that are kept separate or merged based on their identifiability. I haven't fully read through the artist profiles as of posting this but from a cursory look it seem as though they only share a Fanbox account and not all their accounts? If they are separately identifiable they should remain separate.
A similar case: we have obiwan and weisuoxin separated even if they share the same accounts and get (or are supposed to get, as of current standards) tagged together on every new upload.
Another case: I aliased a0lp to team.achv (forum #384794) because it's actually an artist duo that signs off together on all pieces uploaded to the accounts in this artist entry and their works aren't individually identifiable, noting instead to create separate tags if that ever becomes the case.
