As for Alexandria specifically in terms of regulations don't take advice from a public forum - look up the laws yourself and make sure you understand them.

Yes it exists, but as the above poster mentioned, lots of hoops to jump through.

I would recommend leveraging the BP forums to connect with existing syndicators.

I just can't stand of regulations those are not possible to be monitored and just being there because of lobbyists.

I'm not sure if the program is still going on, but has definitely revitalized a lot of the area when it was once destined to follow the way of other older cities that are aging out of existence both in terms of people and property. 

The challenges experienced in the cases mentioned above and elsewhere would be non-existent.

STRs, including 2 of mine existed before AirBnB.  

Acquiring pre-existing rental portfolios?

A tax advisor specializing in real estate can help you navigate deductions, plan for 1031 exchanges, and ensure compliance with ever-changing regulations.

It sounds like you have an un-permitted unit, which is essentially always a risk since there has been no notice to the AHJ that it exists and they can therefore initiate a code case to have it removed in most cases.