Thanks everybody for the feedback!!

Currently my group we just bite the bullet for the 4 stack debuff on the tank, as we don't really know how to avoid the debuff while giving Mr Big Snake the 4 stacks.
If I am able to get through Snake Phase somehow, I think it is highly possible to solo heal twister + final phase (Pray to RNG gods I don't get stunned).
Conflag phase can be done solo healed by using the old "push boss to next phase at a correct time" to avoid all DS.

I'll try to see if I can heal through the snake phase, if can't guess have to call it quits =\
Once again thanks everybody for their feedback!!