Im also working on a squad based system similar to yours! Im glad to see you got yours up and running in the demo. GREAT stuff!!!

I dont know the cpu hit, but isnt spawning new defense nodes in/around a solid object slower than placing the static defense nodes in WED? I think you may be able to shave some resources by using pre placed static defense nodes around structures that are indefinitly static (buildings, large rubble etc). Plus this could get rid of checking "content" when making a defense point, since the defense node is placed in WED. This way you can have more squad mates/enemies since they wont be creating a whole mass of defense nodes (each checking content).

I'm glad to see someone else working on a squad based game! I have my test bed working and I'm making a few levels to test pathfinding and flanking. I will come to you for answers!