The easiest way to beat this fight is to just think of it as an arena fight where you're up against yourself. Since you're guaranteed to go first, the easiest way to win is to just CC them. Visix is probably the easiest way to accomplish this, since she's void you won't need to worry about affinity problems. You just need to make sure she's either fastest, or fast enough that your fastest champ can boost into her without any cut-ins.

I expect something like Apoth + Scyl + Artak + Rathalos + Visix should work just fine. The fear is annoying, yes, but it shouldn't be an issue since you should really all be acting before the boss gets a turn anyway, and Rathalos should have no trouble wiping them out.

I just kept re-manual fighting and i won fairly easy. things just needed to work out the right way

Dark Fae only gets tougher the farther you advance in DT.  That boss fight is all about turn meter control.  You control the team on both sides, so you can speed-tune it to always be in control of the fight.     

I don't know if I fully agree with that - personally I clear top-floor DTH dark fae without any TM at all. Not saying it isn't useful, just don't know if I'd agree with it being a requirement.

That is what is great about this sort of puzzle.  There are various ways to solve it.  Personally, I had to manual Dark Fae until I took the time to program an AI preset with TM control.  With a TM team, I farm Hard 120 in just over 2 min per run.  Gotta love that Lethal Gear.