I purchased a tax lien that was sold the next year with a “warranty deed” The lien was for 2022 taxes and the deed was transferred in 2023. prior to the transfer there is a long history of tax sales and different names paying taxes including a previous investor. how far back does the line of interest go and would the previous investor be considered someone who “holds interest” in the property?

I've sold rentals before and almost always was asked for a copy of my Sch E.Also during the due diligence and inspection, try to talk to the tenants directly to confirm how much they pay, and also if there are known issues that haven't been repaired (roof leaks, frozen pipes in the same area every winter, etc).

Figure out how much you'd pay in cap gains if you sold in 5 years vs selling now and buying elsewhere. 

https://www.har.com/content/department/mlsHouston Real Estate Highlights in September, 2024:-Single-family home sales increased 1.7 percent year-over-year;-Days on Market (DOM) for single-family homes went from 45 to 51 days;-Total property sales were down 3.3 percent with 8,228 units sold;-Total dollar volume was statistically flat at $3.3 billion;-The single-family median price was up 1.1 percent to $335,000;-The single-family average price edged up by 0.3 percent to $415,435; -Single-family home months of inventory registered a 4.4-months supply, up from 3.4 months last September.

She rented them out, occasionally sold for the appreciation, and bought more ... and more, and more.Successful and happy by any standard, real estate enabled Abu to buy her own home and homes for all six kids.

Depending on how long it will take to complete the remaining work and get the property sold, you could also try to find a larger general contractor; one that could self fund the work in return for a higher payday at closing.  

You can ballpark it here:https://www.servicetitan.com/tools/hvac-load-calculatorCould probably get away with 2 well placed mini splits.

The condo proceeds from the HELOC used as a down payment will not be taxed.The tax will come into play when the condo is sold.

In the last year of syndication, when the property is sold, the entire depreciation from past years is reversed ("recaptured").

Something turn-key is typically going to be sold at market price (unless you can find a deal off market as you mentioned).