The seller recently decided to move out of town and didn't want to be a remote landlord entrusting his property to a property manager, so he was uncomfortable holding onto the property (this is a critical piece of information; always figure out what the sellers motivation is and keep the conversation tailored around that).

The key here is thinking critically about how you can get this property below market value so that your value add can really shine through. 

I would note that extreme caution and the assistance of a qualified CPA or Tax Attorney familiar with ERISA law is critical for such ventures.The IRS does not provide specific guidance on your ability to JV with your IRA, for example.  

Everyone has to determine for themselves what their comfort level is, but you also need to be critical of your own motivations, are you investing to maximize your profits, or looking for a hobby to spend your Saturdays on?

It is more critical to you when you are buying rentals because you already have a long term hold strategy so you want to refinance as soon as possible to make funds available for another house (flip or rental). 

Even in very exacting jobs (e.g. space craft design), where even a small mistake is literally a mission critical life & death issue, they use 'rules' to avoid over-engineering (or to use another phrase 'analysis paralysis').The 'rules' for real estate investing are not intended to be exact or fully comprehensive.

Well for non performing notes the due diligence is critical and getting a complete set of collateral files sometimes can be a challenge.

Relating to people is critical to gaining trust.

Understanding how to stabilize, reposition, and manage the rental asset will be critical to your success. 

What factors are critical to making the deal work for me along with hopefully a higher acceptance rate from seller?