I am so down for this! And I love that you conception of Rhaegar doesn't include him annulling his marriage to Elia. That really does seem so cruel and completely OOC to my conception of the character.
I'm up for taking on Lyanna and really love all your proposed lines for them. I'm probably most interested in #2 and #3. But really-- I'm intrigued by every one one of your lines!