Maybe I don't know the character well enough, but I can't think of any mixup HArc has that I'm scared of.
I don't know anything about HNero, though. I just don't know what can overcome the lack of 5[C], good specials, and meter.
My Personal Tierlist™ would be something like this:
Sei, Nero, Roa
Hime, Arc, VAkiha, PCL
Satsuki, Maids, Koha, Nana, KohaMech
Hisui, Aoko, Tohno, Warc
Ciel, Len, Wara, Ries, WLen, Sion, Akiha
Ryougi, Kouma, Mech, Miya, VSion
Meko, Mech
NA
NAC