Question 2D enemy ai PreFab

Hey guys, I'm really new to C# and coding and I'm having trouble. I'm trying to make a game that spawns in the enemy randomly within a randomly generated dungeon, and I want to make the enemy patrol an area of 10 by 10. The problem is that the enemies are prefabs, so I can't just make it a -5 to 5 position as the enemy will move to starting spot (and waypoints won't work as they're prefabs and they'll just chase the child waypoint endlessly). Also this is a 2D game, so navmesh won't work. All help would be appreciated.

 

I do believe that navmesh will work just fine with 2D.

https://noobtuts.com/unity/navigation2d

 

Yeah that may work the problem is I'd have to pay for that