I would make one distinction and that’s between an expense and a capital improvement. 

Right, I asked for books and a schedule for the biz from the return.  

The bottom floor is approved for commercial business and has the main vault, some marble flooring, and a back room office and restroom.

And a business license is nothing and not required in almost all instances other than where you might be domiciled.  

I currently have a 5 unit 3 of the 5 units recently completely renovated and demo is almost complete on the other 2), a duplex, and a single family home (our house, future investment home though).  

Just a year and a half ago, I wholesaled the house directly across the street from this property, making this deal even more meaningful.

It also sits on 2 acres with separate buildings for animals and a nice storage shed.

Selling individually, i would get the most profit but it is 4 times the closing fees and a longer process. 

Most serious and qualified tenants are searching on the major 3rd party platforms you mentioned + realtor.com, redfin, and a few others.Apartments.com & homes.com are owned by the same company and may offer some additional marketing options.Another strategy to consider here is social media - video marketing.

With no RE background and a full time job I was still able to create the right entity I needed, develop a powerful tax strategy, found a partner to invest with, and about to close on a rehab where we will both make $25k+.