Oh, you basically what I have to work with, except I lack Thor while having Cyclops.

For water catastrophe, I use Mordred w/ Chaos Magic, awakened Tyr, Krishna, Sol, and Ramiel as starters, with Nemesis and Cyclops in the bench slots. In your case, replace Krishna with Thor. Because I don't have the pieces for actual serious punching, I have to opt for survivability with Sol. Atlhough awakened Sol turns out to be a great counter to the first trigger attack of our water ragnarok. Ramiel's there for the +10 burst gauge and praying to inflict dazzle. Mordred's there for Black Propaganda to stretch the overdrives out, and of course Outrage for praying to inflict dazzle. Honestly, this team was a holdover from Rahab reprint, then I was too lazy to change it up. Tried it out against water rag and it worked out decently enough for me.

Generally speaking, you'll probably be using Tyr for her defense debuff and Thor for inflicting paralysis.
Ramiel's usually a 4th/5th choice as there's always a use for the +10 burst gauge and usually a use for praying to inflict dazzle.
Nemesis is a good instant offense off the bench choice. Baal and Krishna are probably the next best bench offense choices after her, though they're more 'pray for triple attacks to kick in'.
Sol's.... iffy. So, ideally speaking, you strive to hit hard enough to not need to stick an off-element Sol in your team. But I'm personally not there at that level yet. You may or may not be at that level yet. If you run into situations where you just can't win the damage race, then consider switching strategies to stalling out. Sol normally greatly enhances your survivability, but it will noticably cut your damage output. It's not a trade to be lightly made.
Do tailor the team to the encounter though. If you need a damage cut that one time, put in Perun. If you really need a cleanse, put in Indra. (hell, I'm considering a gimmick cleanse team of Vivian/Sol/Cyclops/Indra against Sloth... xP)