It's tempting early on to leverage as much as you can so you can do more deals and keep liquidity, but increased cashflow especially with PMI will make you sleep a lot better at night.

Basic q - do I have to liquidate to pay him back in cadh OR can I use the stock to pay him off?

Flipping is a production business.

The guy sure knows how to sell products.

When you go to a Bank or Credit Union, they can only offer you what products that bank or credit union offer.

A 1031 exchange allows you to defer taxes by exchanging real property held for productive use in a trade or business or for investment for other real property of like kind, which is also to be held for similar purposes.

We liquidated all of the houses, and I started over after the divorce was finalized. 

I would suggest going to the find a lender tab here on bigger pockets to find a local lender who has the same products. 

Estimates range from $3-500B of property insured with the FAIR Plan and between $3-700M in liquidity with up to $3B in re-insurance.

In addition being able to do your own searchs and one thing out west here that was very productive for us/me was just going through the big Plat maps ( the actual mylar / paper ones in the day) We could find shadow plats.