Things that we have discussed are rights of refusal if either party wants to sell their position; a minimum hold period of 7 years, & only making withdrawals if there is 10k reserve in the shared account. 

If you create a second (or third, or whatever) mortgage on the property, you must be paid off at closing in order for the seller to convey free and clear title to the buyer.

But you generally don't want to use legal docs from other parties without having an attorney review for your protection.

Just needi g feedback like I'm getting to figure out how to make it make the most sense for all parties involved.

I use one divided by responsible party

They say the hardest part is finding the deal/motivated seller and one just happened to fall into my lap here.What do I need help with? 

If it's the standard TREC 1-4, check the appraisal waiver and 3rd party financing addendum and what was selected. 

The hard part is finding the deals.

The experiment part is coming with my analysis...

Thirdly, a ding on a truck is nothing.