Detroit MFH appraisal estimation help?

[Jay Brown]

Hello biggerpockets community and my fellow Metro Detroit area investors.

Currently working on 2 deals in the 48221 and 48227 zip codes. 

1.  On the 48227 property its located on Greenfield between Puritan and Fenkell. The duplex is 2 bed 1 bath units and a total of 4000 sqft. The seller wants $50k but willing to negotiate. I'm having a hard time finding fixed up comps in the area to compare it too. 

2. On the 48221 property, its on Fairfield across the street from University of Detroit Mercy and its a Duplex. It has two 3 bedroom and 1 bath units with 2600sqft combined total. Seller wants 66k but I feel its pretty high for the area. Again having a hard time finding fixed up comps.

I want to make sure I'm buying smart and that what I'm buying it for is "at least" what it is worth in today's market.  Any help would be appreciated.