Dang these super bosses are insane on normal+. Feels like I'm trying to solve a raid. So far I've only encountered and beaten the first 3. Guess I'll leave my strategy I used in spoilers. I'm sure coming back with stronger classes might make em easier but wheres the fun in that?
I hope future mechanics aren't as hard to figure out as eat the rich but I imagine they will be. Really enjoying the game so far even if I haven't run into any porn yet.
Decided to give the bunny boss another try after the new update, since it promised to fix the holy grenade attack, and what do you know, got it on first try. But I had a finely optimized group for it and I still walked away just because in the end I got incredibly lucky. The final barrage of attacks gets stupid and there's basically no defense except pray for good revive luck.
Your tactic re: the RBB combo shield is the easy MVP of the fight. The bun does slash through it at the end, but it is possible to rack up insane values worth of shield if one's patient with triggering it.
The other key element is something 6six6 told me after my angry outburst on TFGames (heh). It's not hinted nearly well enough, but you can cripple the shadow bunnies to only deal tiny bits of damage. The hint is in their color and "name". Inflict the correct status on them and they're done. One is wobbly (Calum's Sleigh of Hand), one is frost (Rime from Thermal Gloves), one is burn (Flint Strike from Gear Ring) and the last one is flank. There's an item for it I didn't have, so I went with Luna instead of Penelope and saved her ult for the shadow. Welp, since it's not 100%, it failed (of course) and the last bun kept terrorizing me during the final push. Boo, hiss.
A few extra useful hints:
Do NOT forget to regularly change tactics, the punishment for enemies adjusting can be brutal and ruin a fight.
Start with Harper on Healing duty, she can chip in with valuable revives if the bunny obliterates you early on with Strike the Ailing when cursed (which is forced on turn 1). Then switch her to Support, you do NOT want her curing your statuses just before a Devour the Rich lands, boo, hiss. In the final push I switched her back to Healing, because the revive carousel became more important than keeping a status.
Speaking of the revive carousel (having to rez 2 chars in 1 round), make sure every character has a rez skill, and you do it in the correct order. Some rez skills may be tactic-locked, so that char has to go last. Also there's one free, automatic, full rez available if you have 4 points in head TF (Face of Adversity IV).
It's good to have Diffusion Strike or mana-stealing weapons available for everyone, it's great for filling out garbage rounds where you don't want to deal high damage and don't need to heal/defend.
And for the end push, just start blasting and hope for the best. It's really handy to have a full charge of Cal's ult and throw it in right before a party-wiping attack, because it gives you one round of invul. I managed to withstand some turbocharged Killer Whatever AoE attack that would've wiped my party like 5 times over, heh. At that point, glhf.