For steddings, I think it's just a matter of making it so that, in an area, the Shadowspawn don't travel (like some kind of code). Channeling is easier. Just make it so that when you pass a certain area, the power weapon disappears, and reappears when you leave (that is possible, right?)
I'm not sure about weaving a weapon, it might not be possible.
Artifacts, I know can be made, but maybe use ter'angreal for most. Simple stuff: an item that makes some food every day, or increases travelling speed, or grants a new weave in game
As for the storyline, I've seen it done before, but I'm not sure how (I've never coded anything more complex than a very basic website). If you need someone to write the storyline (if you do a parallel story, I mean) I'd love to help.
As for removing compulsion on the player, that might be good. You'd think that if a compelled person started killing the enemy anyway, the troop morale would increase, and enemy morale would go down.