Nicki Clyne as Lucca Ashtear? Hmm...
Cut her hair, dye it a magenta color, slap the clothes and helmet on her and whaddya get?
Well, it was the best picture I could find of someone dressing up as her. It was that or this:
Which do you prefer? Me? I like to second one better.
Anyways, take the above cosplay costume and make it look more authentic and world-weary for dear Miss Clyne, and I do believe she can pull it off.
As a side note, I would like to make one thing clear:
Your casting list is a wish list that you shouldn't set your hopes too high on. I've been reading "Save the Cat: The Last Book on Screenwriting You'll Ever Need" by Blake Snyder (the best spec screenplay seller to date), and he says that down in Hollywood, rare is the occasion where dream script meets dream cast. If you cast your movie in your head beforehand, you'll always walk away with disappointment when the casting director finishes his work on your movie.
Actors and actresses claim that they wish to find the acting role that they want and would know how to fill it, but don't fall for it. They have no idea what they're looking for, and it's a pretty good guess that the actors and actresses that you just listed have that same lack of idea as well.
I'm not trying to shoot you down or anything; I'm just being realistic. It's a great list (don't get me wrong), but I wouldn't expect even half of these people to make the cast should a CT trilogy ever became a reality due to either previous commitments or creative differences (I say trilogy because some of the best film franchises came in trilogies; best to follow a formula that has proven successful over time)
Up next: the failure knight known as Frog/Glenn! Hooray!