My first mortgage was almost 11% and that was a good rate.

If it is someone you know you can give them a straight return as if its a loan - can provide a lower interest rate to provide upside - it really depends on the lender and what are they concerned with and what is their risk profile. 

At any rate, I saw someone trying to explain how the @... works yesterday and I tried, but I really couldn't figure it out.

Most seller's in a sub-to don't understand the risk they are taking and most lenders have concerns over the overall portfolio quality ratings which has an impact on their cost of funds.

.🏗️ Building Equity While Others PayWhen your tenant pays rent, they're helping you pay down your mortgage - building your equity.

House hacking can work with an FHA loan, as rental income from other units might help you qualify, but be sure to consult with a lender or mortgage broker to explore flexible options based on your unique situation.Good luck!

On insurance side of things, there is a lot of variables.

It gives you a list of all the assumable mortgages in your area.  

I'm struggling a little bit on deciding the best agreement to make sure I can get some cash flow, payback the HELOC, and not drive the new mortgage up too much with the Refi out of the HELOC.

Refinancing will change your mortgage rate, and if it’s worse than your current rate, it’s not worth it unless you’re getting a great deal.