Terrific post. Been there, done that. Except for the "f-u party" that I had not heard about, all your tips make sense and work.
Nothing like being freed from unnecesary and self-destructive anger.
We are having it now with politicians and their followers and it feels aweful.
With friends, relatives, and ex-partners I guess it is easier. There are usually some links or third parties that contribute to the amelioration of the damage.