@Goldfish, for Qyburn, assuming we can get that Greater Blink neutralized before his turn comes, I'd suggest:
Move - Change Channel Vigor to mind so that he gets a total of +14 to hit with Ranged Touch spells.
Swift - Assay Spell Resistance
Standard - Weave the Sources
-- Thanatopic Enervate, Maximized using a gem (4 Negative Levels, +14 to hit, no save)
-- Decerebrate, with Magical Manifesting +2 (causes braindeath, Fort DC 29 to negate)
If the Enervate hits, the Omnipath takes -6 to his save against Decerebrate (-4 from level loss and -2 from Weave the Sources).
By default, an Omnipath has +18 Fort, so with the Enervation hitting he needs to make a DC 29 check with only a +12. Potentially twice if someone uses Alter Fortune to force a re-roll.
I'm not really expecting this to work since that thing definitely has a bunch of tricks up his tentacles, but this way, it has to blow at least one of them to evade this killshot.