1) Don’t ever worry about offending anyone. The worst they can say is no. Just move on to the next seller. You are not in the business of making friends here.
2) All of it is negotiable in resale.
3) AP will probably come back, but there is no guarantee of that. Weight that in your decision.
4) Check out the ROFR thread to get an idea of going rates for SSR right now. Disney has been exercising ROFR on SSR lately, so it might be worth it to either wait a few months and see if they keep taking SSR contracts or get an idea of what prices they are typically letting pass. Unless you are in a huge rush, waiting a few months and watching the market is probably your friend here. Alternatively, offer a slightly higher price on SSR and cross your fingers.