How can I?

I'm currently making my First attempt of a small project here, is a tower defense but placing heroes in the map and then fighting.

The way I'm making it isn't so clean, but so far I'm feeling satisfied with it, either way, there are a few things I don't manage to handle yet.

1- I'm spawning melee heroes on a ground floor and ranged enemies on a high floor, and I'm spawning an X in the forbiden areas for each of them, but I would like to adjust that X and spawn the heroes to the center of the tile (avoiding spawning them just where the mouse is)

2- When my heroes are being dragged to the map, if I pass them near the enemy colision area the enemies will stop to fight, I've added a condition that the stop will only happen when the hero is not being dragged, but after placing the first hero, the second one will still stop the enemies if I pass him near by the enemies.

Do you have any suggestions abour those things? Sorry, as I said before, is my first time and I know the questions are probably silly

dropbox.com/s/agjz58vjzarw51v/CF.c3p

1. Because the units can be picked up anywhere on the object you can try setting the object to mouse in the same way that the X is set there

2. You should be using 'is dragging' (inverted), you are using is drag n drop enabled which is for the behaviour in general and from what I can see this is always enabled, is dragging is for its use