I'm going to bet that they either blocked or closed the vents in the  master bedroom and there isn't really a problem.Explain to them that you need to get it looked at and if they are not going to organize it, then you are taking matters into your own hand and doing it. 

I think that overall, multi-unit buildings will be your best bet if you don't want to risk getting in trouble with condo associations. 

Your best bet if you want to know that is calling the Section 8 Housing Assistant assigned to your tenant and asking, they may be able to calculate what it would look like.

Just like @Jason Wray said, finding a good agent or already knowing one is your best bet.

With your research that I mentioned above, make the choice where you feel the most confident with supporting evidence.

As I have been building my foundational knowledge for investing, I am at the stage where I am also wanting to keep up with the market data that, so I may better understand the specifics of the market of my choice.

As for the single family house I have no choice but to sell it since I am stupid enough to fell for a pig butchering scam.

I run a call center for Real Estate where we call for investors and I can tell ya, your best bet with such limited time is cold calling targeted lists (high equity within your buy box) for 3-4 hrs every day.

You bet!

Your best bet right now is to live in it and enjoy it as your primary.