Yet in less than 5 years they're sitting at the closing table refinancing with very competitive bank rates.all cash

Not so much to impress others, rather than for your own understanding.You need to be able to prepare a table, to show on a timeline which money goes where.

I want to get into real estate full time, but I can't put food on the table rehabbing one house a year!

My "current year" folders stay in one of those plastic file tubs, right next to my desk (actually a 6' folding table-works better than a desk for me) so they're always close at hand.When I finally got a computer about 8 years ago it came with "EXCEL', as does every other Windows system, and it's so easy to use it's funny.

And we will do this because we see the value of working with people who appreciate all that we bring to the table and those are the folks we want to do business with.

Since I'm bringing so much to the table, I feel I could be just what a REI is looking for.

Your state might even have a title policy table where you can look up what the title costs should be (mine does).

Basically, is there a good resource/place to start/advice for the best options to bring to the table if and when I meet with the seller?

I believe the best jv's are when each partner brings different sets of skills to the table and are equally motivated.  

Nor did you leave any money on the table when they want to break the lease.