This investment should have done very well based on these facts, but the biggest drag on performance was the yearly high "unexpected" property tax expense ($300-500k drag on NI per year).

There are no laws restricting mark-to-market rents. 

The biggest question you need to ask yourself is if you are doing this to afford a property you otherwise couldn’t afford or to save money period, that will lead to very different conclusions about where/if to buy. 

The biggest mistake a first-time investor makes is never buying. 

If you join a brokerage with low or no monthly fees, your annual expenses could be as low as a few thousand dollars.

What are the biggest challenges you face when it comes to assigning vendors, scheduling, and making sure requests are handled quickly?

That being said, liability is often the biggest concern with short-term rentals, and the underwriters have agreed to offer a general liability only policy." maybe dodged a bullet.

Our biggest expense was replacement vinyl siding, which costed around $40K.

There is no statutory prohibition against buying from a related party in a 1031 exchange. 

My biggest piece of advice is to run it like a business especially with the tenant next door.