I assume this is a legitimate business as far as legalities go. I would expect the business to be registered at some level of government. Even if it's an occupational business license from the city or county where it's located. Or could be registered at the state level as a DBA, a sole proprietorship, an LLC or even as a corporate business structure.
If 100% of the property is business use, then 100% of the property taxes would be deductible. However, for the first year the property was not 100% business use the entire tax year. So the deductible property taxes would be pro-rated for that first year. Not a big deal really, and I believe the program will handle the pro-rating for you based on the "in service" date; but I'm not 100% sure the program will handle that correctly. So double-check the numbers yourself on that.
While the property itself is not a depreciable asset, there are times when certain property improvements are. If it helps, take a look at IRS Publication 946 at https://www.irs.gov/pub/irs-pdf/p946.pdf Apendix B starts on page 97, and on page 98 asset class 00.3 covers land improvements which are depreciated over 15 years under GDS in MACRS.
