I have Ariel maxed, and I wouldn’t run her on tank. Much better as a left flank.
You don’t want 2 healers on your defence team as well. I think Aegir and Rigard work really well together, and supporting them with Likes of Marjana, Lianna and I guess for you Chao would be formidable.
Chao, Rigard, Aegir, Marjana, Lianna.
If you max Lianna, this defence will hold you in high 2300 for sure, and if you manage to replace Chao with Joon, you would be diamond with 8hours sleep easily.
Tank is really important peice, both war and raid. Moment I maxed Ursena, everything became so much easier.
It’s the center peice you build around.
I’d start with Aeigir with no 2nd thoughts.