I'm early into the game, and at the part where a bull was screaming for help, i lost to the two slimes and he died. I didn't think much of it at first and continued with the game. However, I've unlocked the quest to repair witers shirt, and to do that, I have to get into a bull village. I visited the bull village early and lost to the 2 initial bulls. Now whenever I try to enter it I get kicked out. How do i unlock it?

(Old topic, I know.) Keeping Thane alive is the only way to access the bulls and their shop. If you fail the 2 slimes encounter, you are locked into the 4th route (found in the guide below).

To answer the spy question: you will need to visit Nauxus (picture for reference) before meeting the spy, and choose to talk.

This info along with many other parts of the game are in Redyoshi's guide (pinned to the community posts). If you are stuck with something after the 0.23 update, refer to the update logs, as they can steer you to the right places.