Huh. That makes sense. I am making a mod for Jedi Academy, and in my project settings it says Jedi Knight Jedi Academy is the mod I have selected and Single Player mapping mode is the map mode I have selected... Could I need to update GTKRadiant or something?
EDIT:
I could not tell you why this happened, but I reverted to a backup of my .map file and restarted GTKRadiant, and the NPC_Player preset appeared in the list. I have no idea how that works. In a pinch, I also figured out that you can just use the NPC_spawner preset and change the classname key value to "NPC_Player" and check the cinematic box. Super weird. Thanks for all the help everyone.