QA-COU-1: A rival of mine likes to play head games, for example by telling me my score for the round, that they think I will make or miss a putt, etc. Can I call a courtesy violation on them?

Maybe. Though being a jerk isn’t explicitly listed as a courtesy violation, any action that is “distracting or unsportsmanlike” can be penalized. You will need to decide if the player’s behavior is bad enough to call. Short of that, it is something you, your group, and/or other players will have to work out with them. If the behavior is bad enough, or there’s a pattern of it for that player, you can notify the TD and/or the PDGA Disciplinary Committee.