I guess a potential option #5 would be to remove the fretboard and see what's going on. I've encountered few twisting necks that didn't have an underlying issue, like a wonky truss rod or poor route. ~1 inch thick of hardwood with a steel rod down the middle shouldn't bend so unpredictably, you know?
Anyway, could get the fretboard off the old way (steaming it) or I've had some where I made a couple passes over the jointer to work it down to near nothing, pulled the truss rod out through the top (after the fretboard is <.5mm thick) and scraped the remainder off with a razor blade. Could replace the truss rod if it's fucked, clean up the route or titanium rod it. I've also had pretty good luck replacing the older fretboard with one +1mm to stiff it up.
It's pretty invasive but it's all shit you can do yourself so it'd save $$$ and you've obviously got the gear.
EDIT: Just realized this was basically option #2. Well, either way there's some added ideas. Steaming it isn't so bad if you go the route of drilling small holes in the fret slots, you run a clothes steamer into a basketball pump needle and let it do it's thing. First few are slow but the whole thing will come off in one piece after the few.