I wouldn't call that incredibly simple logic, pathfinding is difficult however you look at it. It won't be anything to do with a limit of objects on screen as I had a theme park game with hundreds of guests pathing at once. You have some risky events in there running every tick but it's difficult to break down the logic from looking at them.
Returning to the original problem, I don't quite understand it :
I'm trying to create a "pathfinding" sprite that can be used and pinned to every enemy that requires it (essentially only ever having ONE pathfind sprite for every enemy, npc, etc. in the game).
How does the game work? Why are the enemies not pathfinding on their own and instead you've included a pathfinding object that compares its instance var with the enemy UID? Also it looks like your screenshots are cutting off important parts of the events so it's difficult to assist when some of the logic you have is missing from view.