But the forced business arrangement makes it seem like there's a decent chance they're not making that much on the part of the business that's wholesaling you the deal.

Just make sure it's a good arrangement for everyone...

Ask the buyer to arrange for the tree to be removed or trimmed. 

They probably won't give you a 30 year deal, but maybe 5-10 years, after which you arrange other financing.  

My strategy is to find "good deals" below market price of especially single homes , purchase, renovate them, rent them and hold for a while  . like (2-5) years.I need a good whole - seller, or an estimated real estate agent  to work with, contractors and someone who will take care for the arrangements and inspection of properties, and probably a property manager etc.

Also, when my name goes on title how will that affect his prior arrangement with his investor as far as their title status/agreement?

I will pay off his tax debt and we list it for sale lower than market value for a quick flip, it will have room for my desired profit and he will be able to recover 30-40k of equity (vs losing everything)What would you recommend for the contract / agreement / arrangement to protect myself from paying off the debt and being able to list it right away.

I showed up to this arranged meeting wearing a suit, and I'm glad I did because they were wearing custom $2K suits in this low lit bar.  

But most non-private (i.e. hard money, conventional loans) won't allow this arrangement.  

Some arrangements off the top of my head: An option to buy sometime between 18 weeks and a couple years (or whenever).