Agility is nice. We are forced to picture it as a kind of 'physical awareness' of her supermuscled platform of a body rather than ballet skill, but it's hard to go past the dodge bonus AND some initiative AND some mitigation to your stealth difficulties. And Mor'Lag learning magic - perhaps from one of her party members - would be a cool route to take, but I think you're right to set it down the track a bit. It's fun seeing Mor'Lag as a physical wrecking machine who is fascinated by the mysterious powers of weedy little finger wigglers.
I like the spell, and it's fun seeing Marion get power drunk with her destruction spells in combat, so I'm inclined to encourage more of that. 400ft range is hyuuuuuge though. It's like being a magical artillery piece. Is that kind of how you're picturing Marion? Raining fire from extreme ranges?
Works for me. Getting out of the necessary but suffocating confines of 'civilization' and back close to the elemental heart of the world.
While we're talking about it, I'm happy for CP expenditure to happen outside of active challenges as long as the changes are subtle enough it's conceivably understood as the expression of increasing skill; or as the first manifestation of a previously undisclosed ability. So an increase in atheltics, or the gaining of a new fighting technique or spell permutation is great. But if, for example, Zachary decided he wanted to become a druid, I would want to RP our way to something justifying that before the points were committed!