Gregor Nasin - No Barkeep Compendium

[Videri]

OP, you can't cast Alliance on yourself; and if you cast it on Gregor, and then on some guard or something, it will no longer affect Gregor. Plus, the other bar patrons don't matter for the quest turn-in; you only need to worry about Gregor's attitude toward you. If he was dubious or higher, it should work.

I've heard this quest sometimes doesn't work if you turn in all 4 items at once. To guarantee success, you could turn in the items one at a time.