The lots belong to individuals. Some are squatters that just set up shacks on what appeared to be vacant land. The subdivision has designated roadways so these are the responsibility of the Government. The roads need to be filled and maintained. The power lines and other services will need to be run along the designated roadways too.
no. there isn't such a map on the web. I purchased some of the subdivision maps from the mapping section in Belmopan. I think they are $50 per sheet. And they don't name subdivisions - they simply show parcel designation numbers.