In mid December I will be overnighting in Narita, Japan as my connecting flight is on the next morning, 20 hours after arriving from Chicago.

The Hilton Narita is available for award reservation, but I have 2 problems:

(1) My airticket has an X beside NRT (as opposed to an O) which may mean that I am not allowed to leave the airport; will find out only on the day itself at the immigration counter. In the event that I cannot leave the airport, is it possible to cancel the award reservation at the last minute (4pm) and reimburse the points? Any fees?

(2) I am short of 2000 points currently which I will make up for by early December. Could I make an award reservation now and claim the award voucher later when I have the extra 2000 points needed? I could technically transfer AA miles or purchase the points for $25 but I am trying to avoid that.

I would appreciate any advice and thought.
Thank you very much.