Sometimes a simple letter to the underwriter presenting your case and rational will suffice.

My rational always hinges on the fact that, if I'm carrying 100% of the risk as the 'money guy' how does a 50/50 split make sense?

Rationalization is expensive...and it controls you, not the other way around. 

The longer you rationalize (verbally) what you did and/or what you plan on doing, the worse it gets. 

The problem is our debt-to-income ration is too high to support both the mortgage and rehab costs.   

When selling and buying do I need to keep the same ration?

The one thing you must know, without any question, without any hesitation, without any rationalization, is this:  There isn't any one thing you must know...there are many.

Leave your emotions at home they are interfering with making rational business decisions.

For your question about wash, DTI is keyword Debt to Income ration when it comes to getting loans.

I am not a real estate agent but with rentals and tenants, in my experiences, every time religion came into the conversation or it was used as some sort of reference or credit, I needed to block that out and make the rational decision.