Have you been approved for accommodations for another standardized test, like the SAT or the GRE? If so, LSAC will most likely give you the same or better accommodations without additional documentation (Prior Testing Accommodations Policy).
I don't think so. I'm talking about how I want to pursue some kind of government/public policy work. I don't think it's ever bad to indicate if you have a specific reason for going to law school.
I would not bother with it. You aren't going to benefit from challenging the policy. If you were able to convince them to change the policy, they'll probably do it in the distant future (when you're already done with the LSAT).