Looks very cool.
If it's 7-12 then you're going to need to handle spells like fly, dimension door and (at level 11) teleport. I find that forbidance works well for the teleport and dimension door spells, and possibly your ice queen can dispel any fly spells they use, but there might be a more elegant way of handling this.
I certainly look forward to seeing this one done. Great work (and repped for diving in headlong with your first post).