
EDIT: if any bretons want to exploit the games [censored] spell stacking you can take alteration and the shield spell stacks with your racial... giving you 80% or 95% shield for 30 seconds depending on spec...... no reason to make any other race I guess HINT do this with the jane character! With ogre skin shield you have 100% shield, easy /cry
EDIT2: I realize now that my orc will have 50% less stamina drain from armor, knockdown power attack, and shield bash on block which bretons can not get at level 26 of this tourney. I guess it can pay to be green sometimes!
There was a misunderstanding. When you asked if NPCs use their abilities I thought you meant the passive constant effects because these are called abilities by the game. But Dragon Skin is a greater power and has to be activated. These are generally not used. So no, Bretons can't stack Shield, but the 50% Resist Magic is bad enough. And if they have the Atronach birthsign (like Jim does) any magic you use against them is only 25% as effective as normal.
I also presume this means that you can edit the Combat AI so Yurkig can spellcast more often?
I'm afraid the combat style has no effect on spellcasting frequency.