Maybe a third if they were so silent a partner that they would appear invisible to someone with z-ray vision. 

@Karren Braddy From having over a decade of experience in working with turnkey providers I would recommend first to have a conversation over the phone with them and see what they actually provide from A-Z and be sure they are true turnkey providers (with property management) and a real portfolio to look at with multiple options.

The lenders I've visited with have not wanted to do the loan because of Regulation Z. 

If all his income z ffrew is disability and no more I doubt he will meet a 3 times rent formula.

There is nothing different about a contract with seller financing other than the section regarding purchase price and financing.Here's a basic provision:Seller agrees to hold a purchase money deed of trust and note secured by the property in the amount of $x at a fixed annual interest rate of y% payable in equal monthly installments of $z... with the full unpaid balance due, if not sooner paid, on [date of balloon payment, if applicable]

This also manifests on these very forums, the "I'm buying a house, but my loan is being jammed up by X, Y, and Z," threads, where X, Y, and Z, are things that only come up on purchase transactions (income/DTI issues, down payment sourcing, title issues, for example), not refinances ("if they qualified when they got the purchase mortgage and didn't get fired, they're qualified now because the rate/payment is lower, so no need to check income/DTI upfront," no down payments on refis so no need to verify funds / bank statements, no title changes on typical refis, no purchase contracts on refis, you get the idea). 

What is the cost to build, and what is the value of the small lot with a completed build worth (Z)Value= X+YValue =X+ZIf X covers your cost after the rehab and you pick up Y for nothing and can build and sell for a gain that is a win. 

Does anyone have or know where I can find a detailed/lengthy checklist for purchasing property from A to Z?

I really don't care if Institution A gets stupid for Business Type Z.

I come across far too many investors who find a great deal and buy without checking with the P&Z and are stuck with either heavy monthly fines or a property they can do nothing with.Lenders are leery about deals like this.