The mortgages and closing expense can be written off to eliminate the taxes as you want 

If not, factor minimum 15% for management.Also, consider that you will pay taxes on all the income (after expenses).As others mentioned, research the competition in your area to learn the demand/restrictions.Depending on these answers, you may be better off doing this closer to home. 

This is where your experience doing the rehab yourself will pay off.

Where do I start and what makes them "off-market"?

You’re probably better off buying it as a primary and living in half. 

The earlier you start in your RE journey, the better off you will be in the future.

Most mortgages aren't.Without paying off the mortgage it would be a sub-to deal and I think risky for everyone involved

The OP is currently exploring conventional rehab loans (presumably 203k or similar) which would indicate that he is intending to owner occupy, and therefore hard money loans are likely off the table (as most HMLs are not NMLS licensed and don't make owner occupant loans).That said, to the OP, if you're looking at a conventional rehab loan you're just going to have to accept higher costs, less flexibility, and more red tape.

Then unclaimed property will be Auctioned off by The State.

You need to have consistent inventory and be a serious player to pull #1 off, assuming you are in a competitive market.