The NAR settlement is not even yet approved so I would not be making any decisions based on a potential settlement that could be amended.

Examine the property's state, rental revenue, and cash flow while taking location, condition, rental prices, and future appreciation potential into account.Assist your real estate agent in negotiating the conditions of the acquisition and submitting an offer.

When I'm in doubt of a potential cost I get the written bid before I even make an offer or while I'm still in my inspection period.

Or a home with a potentially separate entrance to the basement that you can then STR/Airbnb?

Third, what is the potential cash flow? 

To explain what I see is a lot of potential investors and investors with limited exposure go down a rabbit hole and spend countless dollars they do not have because someone is trying to sell asset protection to them.  

I wont disagree but you may find that PMI is worth it to get into a specific deal potentially. 

I just want to know if this dream is feasible and if I can potentially get some advice from you all. 

Not married yet + HELOC + you not contributing to the purchase all make it rife with potential bad endings.3.

The cops contact you and ask did you ever see anything suspicious, you say yes and the next thing you know you're being prosecuted and also potentially sued by the kids' family for punitive damages.