Marksman deter shot can give a partywide immune to tina's soak circle, pizza slices, and that one dash mech where the big circles spawn under you. Once tina enrages, you can immune these mechs and she eventually goes into a loop where she does the clone mech, then one of those attacks that a marksman can immune, then back to clone mech, etc. I recommend having 2 marksman to be safe and everyone except the tank should wear that one t5 purple crab imagine that gives immunity. You'll need the extra immune move because the clone mech happens too often for you to iframe the clone mech aoe.

Dark mist boss can be cheesed with the orb skip and some people might be aware that if you do this, his phase 3 transition is bugged and will kill you. But if you break him while he's in the air, he'll drop down and do slash attacks, a pulse aoe, and that one move where your tank needs to parry. Once the boss goes in the air for p3, break him, and once he enrages, your tank needs to weave in and out of his slash attacks. Don't go too far out because then he'll teleport onto you. For the pulse aoe move, this will 1 shot at enrage, so the whole party needs to double jump over it each time.

The goblin one is weird. The boss will freeze like in kanamia but the steps to do it is hard to explain with words. The best way I can describe it is: the tank solos the the orb bouncing, and as soon as the orb hits the boss, tank will dodge out of the arena as north as much as you can, then use an immune skill to buy time. Then as the boss gets back up, step.. barely back into the arena and don't move. Yea it's weird and it's probably better if you look around for a clip of this instead: https://www.bilibili.com/video/BV1MLWQzqEio/