Help with war defense please

So my war D has been in flux lately as I ascend various heroes. Last couple wars I’ve been running with Grimm Poseidon Rigard Zimkitha Kingston or something along those lines. Doing ok so far. We use purple tanks and I luckily pulled an Ursena last AR that I’m working on to replace Riggy. The crux of my dilemma is that I’m pretty much ready to ascend another yellow 5* and I’m thinking about using 2 yellow flanks with her in wars because my only ascended blue 5* is Miki (who I feel would often never fire flanking Ursena). I have Neith Joon Leonidas and even another Poseidon to choose from, and my question is basically twofold.

  1. Should I stick with a rainbow defense when Ursena is ready and use Grimm, Miki, or Triton as my blue? Which hero? Not sure the family bonus increase with Triton would be worth throwing him in there for wars that aren’t field aid.

  2. If you like the two yellow flanks route and we roll with something like Zim Posey Ursena xxxxx Kingston, which hero out of Neith Joon Leonidas and Poseidon would slot in best at RF? I mention the second Posey only because I believe it gets the 5% defensive bonus but I’m not really leaning that way as an option (as cool as it would look) especially with two other fighter class in the team. I think Joon or Neith could work. Neith isn’t an easy hero to get a read on I know there’s a lot of post nerf disappointment. Zim kind of has the weak AoE with some added utility role covered already then again I have no shortage of snipers either. I did read the recent topic here comparing Joon and Neith to each other. She does have that element link too for Poseidon which isn’t worth much but it’s something.

I’m a fan of rainbow defense generally but this situation might be an exception. Any suggestions? I only have at most one ascended 5* at each colour right now and for the foreseeable future. Non maxed purple 5s include Sartana Kage Victor Domitia Thoth and Obakan. Non maxed 5s of other colours include Thorne LotL Kadilen Grazul Mitsuko and Khagan. As you might have guessed I have pretty much every 4* you can think of.