You can expect at least 1 tenant to put up a fight and force you to go through the eviction process.

As you grow and get into bigger deals you'll be forced into ARMs so take advantage of the long-term loan while you can - just my two cents.Also, I'd talk to more lenders and see if you can find lower rates and maybe someone who will go up to 80% LTV on the 30 yr fixed refi. 

Does county/ city typically change zoning out of the blue, and they can literally force us out of business by re-zoning the land to residential only in the future?

Remote workforces and e-commerce trends have significantly impacted retail and office asset classes; however, the multifamily asset class has seen relatively little disruption.

It is on Amazon via Kindle and is short (~50 pages) but gets to "the point" and gives some really high impact points.

Most Likely a scarcity mindset will set-in and it will impact your decision making processes on your investments. 

I may refinance after the forced appreciation or explore a HELOC. 

Purchase multiple properties with heloc using it as a down payment (try to force some simple sweat equity to brrrr back DP)3.

They forced the City to stop dumping sewer water in the River and even now on hot days it smells awful under the bridge at Platt Street across from the Convention Center.

That way, your DTI won't be impacted by the Phoenix mortgage.