One reason I donate to 501(c)(3) charities through my donor-advised fund is to make an investment in my local area.

I have 6 tenants, though one is on financial assistance with a charity (not S8). 

The GC isn't running a charity and neither should you be.So if you told them or had a contract with them to do it at cost (without any stipulation as to what cost truly is) you would probably be able to argue that you should get the actual true expenses plus some admin fees and your time on the job without profit. 

I am currently involved in a charity out here in Denver that helps those in financial crisis.  

I wouldn't have done much worse if I gave them to a charity.

If you wanna help families, do charity work.

The following IRS website covers the UBIT rules. https://www.irs.gov/charities-non-profits/unrelated-business-income-tax

I am setting up a Foundation where at least 70% of the proceeds from our RE investments will go towards local, national and international charities.

I really think the " QUESTION" is do you raise rents... if you do you keep up with inflation, if you don't your a charity,, Does the gas station at the corner care if you drive a beater or a new car??

We have charities for those things and they have worked for hundreds of years.