However, there’s a catch—I’m looking to partner with an investor to help provide the capital needed to complete the deal (would need to raise around $200,000-500,000).

Don't expect to agree with everything he says and be aware that no one is always correct. 

Maybe also consider if they are "good people" that work in the community and just want a safe place to raise their family. 

Well aware of the ins and outs of real estate and different entities. 

Cashflow – the numbers look good and give me leeway if I have underestimated renovation costs, over estimated rental income achievable or make other mistakes I am not aware of yet!

Last year January MN enacted the biggest # of changes all were added details and raised the bar of requirement for Landlords, including some specifically detailing how a listing must be detailed.

Detroit is a great city to invest in one just has to be aware that is is a block by block city and to be careful

Without accounting for management fees (I have not yet decided if I will try to self manage), and with planning to raise rents to typical market of $825 for each of the smaller units, and $1200 for the larger unit, does this seem like a worthy first investment? 

Is your insurance aware of it? 

I suspect that number might be raised.