In summary, here's what I all tried:
Raised temperature to 72 degrees
Stirred up yeast 1-2 times per day
Pitched a cold-crashed, decanted 2-Liter starter of WLP001
Added yeast energizer
Transferred beer to a different vessel, pitched a 1-Liter starter wort onto the yeast cake, transferred the beer back at high krausen
Added 4 oz of corn sugar
Pitched an entire, actively fermenting 2-Liter starter of a different high-gravity yeast strain
None of this did anything, except the very last. Since pitching the starter yesterday, the gravity has come down by 1 point. Hoping for a couple more points, but not holding my breath.
I think I've exhausted all possible options. I am going to rack to 2ndary with bourbon and oak chips and let it age 3-6 months. I can only imagine how much oxygen I've put into this beer with all the stirring...
Maybe this will be useful for future brewers. In the future I would replace some extract with corn sugar, reduce the adjuncts, mash colder, and have a much lower target FG (like 1.020) so that missing by 5-6 points doesn't matter as much.