I think you may want to leave the defense this way mostly due to emblems :
No point of stripping Kingston for either Killhare or Fenrir ( have him maxed and love him on offense but he needs proper set up of team and specials to become super effective vfast blue ) or Zim for Lepus( especially in this meta ) - a lot of resources for marginal or no improvement
Ursena is better than Bunny in wars as is punishing a colour ( as u flagged yourself )
Alasie is the best blue against Mits imo - hits one target with high chance to pierce, Finley always dies even if he pierces one or two as he hits all
If you had Vela would have been different - i think Sesh GM Tellt Vela Drake is at the top of the meta as a defense - more scared of this combo vs Jabba replacing Sesh - that dispel from Sesh ■■■■■ up a lot ot game plans ppl have for dealing with Telly, GM, Vela, Drake
P.S i will be ascending both Killhare and Lepus as have ideas for offensive teams but both aren’t getting emblems - Vela, Kingston and Poseidon as 2nd one i started are having my emblems in these classes