Original basis (unadjusted basis) is simply what you paid
for the building (not the land).
Adjustments are then made to the original basis for improvements, depreciation, etc.
------
Homeowner Dues:
I list them under Management Fees as the dues I pay, while some are for repairs, maintenance, trash, water, they managing the place and collect the dues each month.
They can be listed a number of areas, however be consistent and list them under same area, year to year, and this will help you compare years to each other so nothing is overlooked.