The only thing that you have said that makes me question the PM outright was the lack of a key for the sheriff to gain entry.

If you are talking about Tax liens you aren't buying the property but the credit of the unpaid taxes on which gaining interest.

My goal is to work with those existing property owners to remove them entirely from the day-to-day operations of their STR, making their property a passive revenue source. 

Not positive but I think you have to recapture it just like any sale.. so if you got 50k write off you will have a 50k taxable gain ????

Just an intro, My name is Yonathan and I am attempting to land my first ever Co-Host position EVEN alongside another co-host working for even free just to gain experience and reputationWould someone or someone they know be willing to “take me under their wing” as to learn to manage the day-to-day ops on behalf of a host?

Just from a fix & flip it looks great but have you considered a 1031 exchange to avoid the capital gains?

To gain premium tenants. 

I've got a deep discount on a truly passive STR.I've got a lead on a deal that can be purchased almost $100k under list price given the circumstances.

You can listen to the 1,000+ episodes of the podcast, read the 10,000 blog articles, any of the 40 books, and otherwise immerse yourself to your heart's content until you feel ready.You can browse markets, look at deals, learn to manage properties, practice analyzing deals or estimating rent, and meet with Agents, Lenders, Property Managers, Tax Pros, and Syndicators offering Passive Investments. 

Not having a mortgage is very powerful.I also like buying properties in my ROTH IRA and not ever owing any further tax or capital gains.