It only matters that a person "perceives" they are being discriminated against, in order to file a formal complaint.

For the  initial offer, you could use a letter of intent style offer letter, rather than a formal purchase agreement.  

Second, while I'm not familiar with your location, I wanted to put it out there that when you do move on from that property, you might also consider doing a  medium-term rental (30+ days) with your property for a couple of reasons:  1) most jurisdictions have little to now formal requirements for rentals over 30 days so you don't run up against the restrictions the STR market has and, likewise, there is not currently anywhere near the saturation as with STRs.

You would still need to do a formal eviction.

I brought my contractor in, he formalized a bid breakdown.

At the suggestion of other very helpful local investors, I decided to attend the judicial tax sale in my county.

Or should the ad be kept more professional/formal and ask those interested to reach out for a short phone call where they can explain what they are looking for, why they are interested in the property, etc., and we can get to know each other and see if it would be a good fit?

This is especially true for most business owners who tend to operate pragmatically rather than following all the formalities required to have all those entities be respected.And you are correct, if you pay yourself all of the profits out of the C Corp it will avoid double taxation but you will be taxed at your ordinary income rate not the new 21% corporate rate.

I spoke to the tenant on the phone and am following with a formal written mail.  

How do you formally inform a prospective tenant that you don't want to lease the apartment to them?.