To what extent will the parties be free to carry on other businesses - while the joint venture subsists- if one party pulls outIs it intended that spouses/partners should also be shareholders, to allow for tax advantages from a broader split of dividends?

If he comes back with $2.3 million you ask him to carry some paper.This is how you make your $5 million in 5 years.

In a duplex if you live on one side and your tenant leaves or unit is vacant your carrying the whole mortgage.

Although it will take time, you’ll get more utility from carrying forward whatever remains after deducting the $3K max.

If you don't want to carry any open debt, then the few times you want some it'll always be this hassle.

I'd rather have the owner carry at 6% interest only for a period of a year, while we renovate substantial fixers, and I get these terms repeatedly (because I ask).

You might be able to find owner financing or an owner willing to carry a 2nd to pay for most or all of the 20% down on the next one.

I'm also very surprised their old insurance even talked to you, let alone told you they no longer carry that business because of non-payment..."

One example of a deal I  am working right now is buying a set  8-12 of seller financed units using my ROTH as a down payment and the owner carrying a non recourse seller financed note.

Maybe they would carry back the debt on the other half.