Which is the most farang friendly place in Issan? (Things like availability of western food, especially vegan / veggie, book shops, fun.)

Being suitable for farangs, i suppose that place would be less like the rest of issan, and therefore lacking many of the benefits of being there. Am i right?

Udon Thani is your suggested destination!

At least 3000 farangs living there know the answer to your question.

Udon has lost little of its Thai-ness due to the farang population

Good luck!