Well how do you define "Support" I guess is the question. Nekmo is a Support and Eostrid is a support. Both Heal through other factors, Nekmo keeps Leech out (which given the high dmg in Hydra teams, is big heals) and Eostrid does consistent heals with TM fills. Both also do Speed manipulation, Eostrid boosts dps with Inc Atk and Weaken while Nekmo reduces Atk of Hydra Heads. Neither have a Cleanse.
Freya is a Triple Buffer so 9 Piece Protection Set may be very Viable, she does Cleanse + Block Debuffs and TM fill (which Nekmo and Eostrid also do). Her "Heal" is Death Prevention of your Top DPS and Team Shield which could end up being a very VERY large shield.
Eostrid and Nekmo are both top tier Supports for Hydra, I think most would agree.
Freya is essentially a Brogni that Full Cleanses AND Provokes, except Inc Def instead of Inc Atk. Brogni has a Reflect ability (that is pretty chaotic with how it interacts with things) from his shields and Freya has a counterattack from her Shields. Brogni grows shields with his A2, Freya grows shields with a passive 50% Inc Def that stacks with her 60% Def Buff.
If you consider Brogni a great Support in Hydra, then again I'd have to argue Freya also qualifies maybe