Or is it mostly just a play to decrease volatility in booking rates? 

I didn't want the hassle, so I am taking about a 10% decrease in revenue, but I have less to deal with.

Also, if zoning restrictions were to be relaxed, could the area end up like others with abundant supply, potentially leading to a decrease in property values?

In nearly every case, the IRR continues to decrease the longer the property is held even though the cash flow is increasing.

Subtract depreciation, explained here:https://www.biggerpockets.com/forums/51/topics/1121063-expla...Because of Step 2, depreciation, many cash-flowing rentals end up showing $0 net profit, resulting in no tax increase and sometimes in tax decrease.

The multi-family market has remained strong, and if rates decrease I think we see more buyers in the market irregardless of property tax increases.

Can you consolidate the portfolio (sell a few properties) and decrease your debt? 

Your price range is very doable in the San Antonio market as prices in TX have continued to decrease substantially over the past quarter.

And lastly, I search FunishedFinder listings nearby, find comparable properties, and track the listed rent for a few months (does it increase, decrease?).

Prime rate runs ~3% higher than the Fed rate but as others shared unlike residential mortgages with the prime rate there is a direct correlation and as the Fed rate decreases so does the prime rate.