If you don't have enough in the IRA to do the rehab, you could partner with your IRA, but the partnership equity breakdown needs to be defined from the beginning, and every expense needs to be split by the partners according to their % ownership.  

I was a property manager a few years back in C neighborhoods in the Midwest with a great value add components to them when looking at a purchase.As far as your numbers are concerned, here are several things you should take into account with the run up to the closing:Deferred Maintenance: are these all sub-metered (water/electric/gas)?

This is usually defined by the plan, and typically ranges from age 55 to 65; however, the actual retirement age may vary among plans.

Or help identify the key components or variables I should focus on when analyzing duplexes?

I would call an a local HVAC company with a good reputation to survey see what they charge for  the components and see what they charge for  a service agreement on the existing.

Define your long term goals, put a plan together then assemble the right team to help you execute that plan.  

Did you do a walk through of the home and get a could feel for the age of the major infrastructure components like AC, furnace, roof, hot water heater and kitchen appliances?

I learned troubleshooting to the component level when I was in the Navy working on multi-million dollar radar & computer systems.

However, there is a De Minimus Safe Harbor election that you might be able to use to expense the full amount rather than depreciateFor all other assets, there are pre-defined depreciable lives, but the methods are where you get some options.Here are some items to know:More than $150,000 in active (W-2, etc) income means that your losses in real estate are not deductible at all.More than $100,000 but less than $150,000 - your deductions are phased out, but you can still partially deduct up to $25,000 of passive losses IF you actively participate in them.  

Both scenarios are fairly meaningless now except for the theorized equity that should be present.The loan is defined as a step up loan.