Could anyone share their experiences or timelines tracking regarding the initiation and costs of property renovations?

Initial purchase to buy/rehab should be around ~15%.

CES often have an initial rate that is lower than a HELOC.

Any way you could buy a outdated home and add value while keeping list price down? 

How can I go about obtaining a list of properties that are tax delinquent and/or have code violations?

You won’t end up in tax court but if you do, you would win based on everything you cited about material participation as long as you have a time and activity log that shows your tasks and provide a guest list that shows the number of nights your guests stay (easily found on the various platforms). 

You can search the internet for stats on where it is initially cheaper to purchase than to rent.  

To be honest if there's not enough complaints to warrant a refund and your listing is a few years old with plenty of 5-star reviews, I wouldn't worry about it at all.

This property is on the MLS currently listed at $540k.

The ($597k) is the initial equity invested, the $220k is proceeds from a refinance, and the $1.2 MM is sale proceeds.