Write a contract that explicitly details who is responsible for how much money, who is responsible for what parts of the labor, who is responsible for "managing" the project, if either of you is to be paid during or after the project, and who is the sole owner or how the ownership/profits/etc will be divided. 

You can do it yourself but you want to tread carefullyThe difference is that the IRS gives a lot of extra scrutiny over arrangements like this because it is very easy to create a step transaction and reduce the arms length nature with the unrelated party. 

Not being able to soak an arm or a leg in hot water in my home isn't acceptable.

“technically”As you stated, there is nothing in fannies guidelines that explicitly addresses this scenario so you introduce the concept of “underwriter discretion”  Scary word. 

The alternative is a nice big rent hike at the limit of legal acceptability, like 10%, and the explicit threat of keeping them coming.

So you could go with a traditional turnkey company or a hybrid turnkey company which involves an agent selling you properties from the MLS / Zillow / Their listings along with a property management arm in house to take things over post closing. 

Make sure it explicitly explains the process for termination if you are unhappy with their services, but especially if they violate the terms of your agreement.3.

@Vivek Shah, if your mortgages have been sold to Fannie, they explicitly allow transfer of title to a LLC.

Make sure it explicitly explains the process for termination if you are unhappy with their services, but especially if they violate the terms of your agreement.3.

I am also a 6'4" 235lb. man, armed of course and let's just say very highly trained in defense (just painting the picture for you).