Screening ALL your tenants rigorously, the same way is the best bet for success with a market tenant or section 8 tenant.

With covid would duplex or small apartment complex be a better bet than single family properties against a real estate down market?

Natural, organic elements are popular and moving away from heavy, dark wood, and farmhouse rustic style (thankfully). 

I bet it will be prominent.

S-corps are not as popular as before thanks to tax reform of 2018.S-Corps do bring with them some additional compliance costs(Corporate formation, payroll tax returns, s-corp tax returns).If you go ahead with it - make sure the savings are greater than the additional costs/headaches.Speak to your CPA before proceeding.

This is what actually Is costs you to get your equity, you are paying every month out of pocket.look your property looks good if all 4 units where rented your analysis that it will appreciate with out doing any value add is a bet on appreciation and rent increases year over year is a huge gamble and only pays off when you sell and if you sell at that price at the right time. 

If you do decide to cash out, you can always place a smaller bet.

an agent I usually do business with has done the same thing to me. im also in PA. learning to navigate this way of doing business has been challenging. best bet is to keep an eye on your market and be ready to strike. but just not to eager as I think prices are going to soon be in decline.

I figure there to be many others who were investors first, and then eventually got licensed, those are probably your best bets. 

I ran and operated numerous short term rental properties successfully between 2007-2015 wayyy before Airbnb became so popular and everyone in every corner decided to do this as a form of extra income.