Alright, I'm trying to learn how the new editor works. I created a duplicate of a Dwarven Centurion, and dropped it into a cell of my own creation. I also removed the steam spell and added a Shock spell. When I test this in-game, all the centurion does is walking around, looking at me. It does not shoot the spell nor engage in melee combat.

What causes this? I haven't generated NavMeshes... if that has an impact.

I also created an NPC, to which I added a spell and a sword. The spell is quite powerful. But he almost never uses the sword. Sometimes he strikes me once with it in the beginning of the battle, then he only uses the spell after that.

Any ideas?

Yo bro, I had the same issue.

I hadn't NavMeshed the cell, whereas after I did, they behaved fine (and stood where I placed them, damn sneaky actors).

Just as I suspected then! ^^ How does NavMeshing work then?

For your second issue, the propensity of an actor to fall back and\or use magic attacks is controlled by their combat style.

Which combat style is suitable for an NPC who should use both melee and magic?

navmeshing is similar to the pathing in the CS(but way less tedious). This is a triangular grid that tells NPCs where they can safely walk on.