I think there’s kind of an unspoken social contract with both the lone boys in these groups: they wholeheartedly embrace being in girl bands — and, in turn, they’re not excluded from any team activity on the grounds that it’s Just For The Girls. Honey wouldn’t even think of not inviting Zero to this thing.
PS: check out this thing I made as an exercise in representing these characters iconically with minimal detail: (click for actual size)