There are a few areas that you need to analyze: Operating Revenues, Operating Costs, Repair (one-time) costs, and Financing options.
I would start by looking at the after-repair rental rates for both 2 and 1 bed units, multiply that out by your 10 (2 bed) and 10 (1 bed) units to get a total monthly revenue.
Then, figure out the cost of repair per type of unit (~10-15K/unit depending on finishes and extent of repairs necessary)
Figure out the cost of repair for common areas (exterior, hallways, parking, main utilities, etc).
Use common metrics for operating costs (10% management fee, 10% repair, 10% vacancy etc, 10% capex, etc.)
Then figure out the NPV of the deal with both of the financing options to see what works better for you. It seems like they are essentially charging you 6% interest if you finance it... so if you would be doing a commercial loan, you would use that interest figure to compare against their rate.