He isn't telling the police, because it is really weird, and he doesn't want them to think he is even more of a freak. The whiny dumb girl begged him for a job as his personal assistant after she lost her bartending job and he said yes since he is a nice guy. The P.I. business hasn't been started because that was the whiny girls idea for why he would need a personal assistant and while he may do this eventually it isn't terribly important to him. After he introduces the detective and bar owner the second time he says something like "I think you guys already met once." (I think they included this so people would see that while he "knows everything" he can momentarily forget about having introduced them before just like other normal people). Same clothes all the time? just his style maybe. As for the acting I could make some excuse about him playing a guy who is a confused walking encyclopedia with no life experience, but yea its still not the greatest acting.