Aristos
Lightseeker
It's way more annoying when a city-state settlers can't find a good location to settle and end up just wandering around for the rest of the game. On a completely unrelated note, you get -10 resting-point with all citystates by grabbing that settler.
Depends. Sometimes I want to increase MIN_CITY_RANGE to 4 or 5 (makes for a heck of a game on a large/huge map with the better maneuvering performance of G's AI.... hello true battlefields!), and in the case of a value of 5, the vanilla code did not let the AI CS settlers move from their spawning positions, and all those who happened to spawn 4 tiles apart (which happens in most cases), just did not settle at all... that was far worse than the case you present.