Before I answer, just for me, if I understand you correct:
(LOL sometimes discribing a problem is not that easy )

You have low poly model who acts as a node.
You assign a action to it called "pathfind_node".
Then you want a function who creates lots of such low poly models and align them in a for example grid pattern.
You want to drop the models on your terrain, so you're intresting in a special hight, too.

So, you need a function who does all this ?

Are these your problems?

Bye G.S.