Not that I advocate excessive use of qualifiers, but I wonder if these tags for specific PVs might not benefit from a _(vocaloid) qualifier.
Maybe not, but the thought crossed my mind. Might be useful to be consistent about it if the next big PV is called something ambiguous like, "Sakura" or "Zettai Ryouiki" or "Cat" or something.
As for these, I'll make the implications for now.