About the house and property lot that you mention, on or near the base in Okinawa, well, the good thing is you seem to not be living on it or near it.
If there happens to be a Catholic chaplain at the base, you may want to talk with him about it.
If you don't find one easily available, you may want to look at the site below.
They may be able to refer to the office where you may find a priest in your region.
I know the Japanese government is working out many details with the US gov, to reduce the uniformed population in Okinawa. I hear they are transferring many officers, NCOs and enlisted personnel to Guam and to the Philippines.
But still, the people at milarch.org are the ones to talk with, concerning Catholic military chaplains inside and outside of the US.