1) Courtesy runner... A courtesy runner is a runner who runs for another player without it being a charged substitution. (ASA Rule 1 DEFINITIONS).
A courtesy runner may be used for the pitcher or catcher only (ASA Rule 8-10A).
A courtesy runner may be any eligible substitute who has not been in the game (8-10C).
The courtesy runner for the pitcher may not be the CR for the catcher (and vice versa). Note: this is position, not person. If you sub for a new pitcher, the same CR for the old pitcher may be the CR for the new pitcher. If you move your catcher in to pitch, the CR for the catcher may NOT become the CR for the pitcher (8-10A).
A courtesy runner is not a charged substitute, so she is eligible to be used as a sub for any other player in a later inning (but not in the same inning she ran as a CR - exception: injury / DQ and she is the last sub available) (DEFINITIONS and 8-10D).
The DP may not have a CR, even if the DP is batting for the pitcher or catcher.
The "pitcher" and the "catcher" who may have a CR is the last player to play those positions in the last half inning (exception: first half of 1st inning - they are the players listed on the lineup card in the F1 and F2 positions). IOW, you may not have a CR for the pitcher or catcher you intend to enter in the next half inning (8-10B).
2) Pinch runner...The ASA rules do not specifically recognize the "pinch runner" by name, but it is just an ordinary substitution. You may use any eligible substitute as a pinch runner. Once you substitute any player on offense (including pinch runner), that sub may only bat / run in that position in the batting order (ASA 4-5C). Again, this is batting-order position, not person.