How horrible!!! I lose my mind if it lasts a day. I feel for ya.
Drink LOTS of water, always, not just now. Longest I ever had it was maybe a week. I tried everything on your list, tried chugging a coke, drinking REALLY strong coffee (which did help some temporarily), eating pickles, drinking pickle juice, saltine crackers, saline mouth rinse... if I could think of it, I tried it. All I did was ruin my appetite.
One thing that I do notice, though, is that my nasal passages can also dry out, so I do use a saline nasal spray fairly frequently. You could try that, or a Neti pot. Those things are awesome.
There's also a thread here about Oil Pulling. It's kinda yucky, helps with oral hygiene and such. Can't be worse than vape tongue.
http://vapingunderground.com/threads/oil-pulling.51721/