If going with a full custom plan (e.g. you have a unique lot layout that will require a customized layout)… closer to $10K, including construction drawings, title 24 energy report & electrical layout, permit processing-Permits: $5K is typically what the total costs to the city will run for an ADU, even with the waived feesConstruction costs: $250/sqft + $10K-Building costs: typically $250/sf to start, for vertical building only.

We aim to hit line drive base hits over and over with our approach.

Investing in a market with a strong and growing economic base can help reduce the chances of depreciation. 

I am an experienced real estate agent/investor based out of Columbus, OH, but spend part of my time at a family house in Ellicottville, NY.

Unless this is an opportunity where you are going to come out with a robust knowledge base and the investor will be a complete open bookd i don't see why you would do this.

DSCR (Debt service coverage ratio) loans don't consider DTI, they are based on the property's ability to cash flow.

You will need to submit a zoning permit, you will likely get a refusal where you will need present architechual drawings.

Based on your post, I would say you would be looking for a DSCR cash-out refinance and then use that to contract a builder. 

Its not likely that any one investment is correct, rather a mix of investments based on your long term goals. 

Even facebook will have several "Michigan" or "Detroit" based real estate investor groups.