[Coda]

... derp. DAthena is dark/water, not dark/wood. Will work just fine with Aizen.

You don't have to have the whole team be water-element. You just have to have at least one monster with a water element, and since DAthena herself has a water sub-element then you don't need ANY others as long as none of your active skills would get rid of your water orbs.

R.Haku is a good fit. That particular Okuninushi is good too. (Probably better than Awoken Okuninushi.)

R.Pandora is a "no." She lacks TPAs.

Too bad you don't have Lumiel. She's awesome.

So... DAthena / R.Yomi / R.Haku / Okuninushi / Beelzebub? That seems solid.

EDIT: That team is a bit short on RCV though. I would swap out Beelzebub for Bleak Night Daughter Pandora, Valkyrie Claire, Persephone, Mistress of the Old Castle Kali, Chibi Lilith, Dill Sirius... basically anything with at least two TPAs and good RCV. I'd say Xin Hua but you don't have enough MP anymore. :P