.- Are there any decreased value on these properties due to the ongoing HOA fees even after paying off the loan?

My wife and I are Realtors and real estate investors, and have helped clients employ this strategy to either significantly decrease their housing cost or eliminate it completely by having others pay for the mortgage. 

I would want to know what is fueling the demand in rentals so that I can confirm that it’s not temporary or vulnerable to a downturn in whatever that fuel is.

Having the extra $150/mo without PMI is massive  Your rate isn’t bad, and though you didn’t list the interest paid last year, it will be less this year and the decreased interest will accelerate as you go through the loan term. 

This leads to temporary and artificially high valuations on some properties.

If we reduce leverage we may get lower cash returns however we do increase our ability to 'stay in the game' and not be forced sellers should rental rates decrease or vacancies rise.

I personally would rather have a garage than additional square footage and in a lot of markets where additional square footage is cheap garage conversion may decrease value. 

Making sure things rent easy to long-term tenants and at least break-even during a downtime when travel might decrease to cover downside there.  

With the above factors, the vacancy rate will start creeping up from the historical lows of 1% which will cause rental rates to flatten or begin to decrease, which in turn should translate to a cooling of purchase prices. 

Can I just get a temporary construction loan, and while paying only interest I take my time to sell it and once sold, I pay off the construction loan?