Is Hailey's side quest just not implemented yet, because I've been trying to work at the saloon when she is there but I can only do it before she shows up?
Yes, you're correct. Hailey's side quest has not been implemented yet, and I apologize for any confusion. It will be included in the next update, so you'll be able to interact with her at the saloon as intended. I apologize for not clarifying this earlier and appreciate your understanding.