The final fight is pretty hardcore, yeah. But it's definitely not impossible. Remember you can back out before going down there and make sure you got the best equipment and skills possible. You can also get permanent apotheosis. All the other characters move by the same rules as you do, with the exception of the Kraken who has indigestion and burps up a couple of annoying dudes whenever. But remember they are soulbound to the Kraken, so if it goes down so do they. Furthermore you don't have to defeat them all to win the fight, though I leave you to find out which of them are the big bads.
Sallow Man's debuff can be removed by all heals, I'm sure. Kemm is vulnerable to indirect magic attacks as far as I remember.
I think you can do it if you stretch real good, take a day's break, and come back at it with fresh eyes.
