Thread:CureHibiki/@comment-31425589-20170420201344/@comment-26868869-20170426200814

They reappeared, but they haven't become mascots. Come back to me when they get sold as toys or become major fairy characters (Kuroro applies on the last one, so he is a mascot.)

If we rephrase it to say "they were fairies after being purified", this applies on the first three options you mentioned (Kuroro, Bad End Trio and PhanPhan), but they used to be fairies already who simply took on a different form, so maybe it is closer to say "they were revealed to have been fairies all along". And this does not apply on the Thieves as they were confirmed right away to be fairies, just "evil" ones.