I thought that Heph and Bryn's buffs/debuffs/heals would be more effective long-term. Plus they're not awakened yet, so they both more or less look like suicide attackers to me.
My Light team is what I'm used to, so I guess I had my Fire team trying to emulate it. Should it be a different playstyle, then?
Fire's playstyle is alot more offensive then light so Bryn doesnt really fit into that archetype.
Running heph over unawakened acala is not unreasonable but all 4 of the kamis in the lineup i described outclass her.
If you need to hit the def cap for solo content you can run Herc with her relic and sniper shot shot but with that team you generally shouldnt need to if you have levelled you grid.
Do awaken Ares when you can though she is quite good.