I understand that it's probably difficult. I've agonized over dropping characters before and You've had some characters here for a very long time. However it's probably best for you as well to destress yourself by lowering your commitments, rather than posting with one character and realizing you have to scramble to make AC with another one.

some questions I would consider thinking about this: whose voice is coming the most easily? whose tendency to get involved in big-time plots and such requires the most commitment (do you have time for those commitments?)? do you have a hard time coming up with posts for some of them? posts are the basis of AC in para though comment threads can count for passing AC. I think if you give yourself less to commit to you will probably do better with the commitments you have.