And can I get this quite clear: The assigned recipient lists one or more characters, of which I have offered to write at least one, but I get to choose who they're paired with, subject to agreed/requested genre and rating and excluding non-acceptable characters. Yes?
Yep. I ask for a, b, c, d, e, or f. You offer a, f, m, l, x, y, and z. Therefore, you can write either a or f - and paired up with anybody the recipient doesn't have on their "please god, no!" list.
Green? Really? Hee! I'll check it out (but it's not green on my browser *g*)