For advertiser contact, send the same short questions each time: Is it currently available? Which floor-area figure is correct and what does it describe? Is the pin accurate? What is the next step for a buyer outside Japan? Consistent questions should make the replies easier to compare.
I would organise the enquiries into three columns: money due before completion, money due annually, and liabilities triggered later. Put tax, conveyancing and registration in the first; service charges, management, insurance and maintenance in the second; then sale, early exit and estate...