Rate caps are around 5-6 for 4-plexes in decent areas. 

I agree.I don't think the golf simulator will guarantee you extra income, bit the ADU would get rate extra cash.

She still left a one star review and airbnb refuses to remove it because it was her "experience" at my property even though I dont have a single other rating out of 30 thats below a 5.Anyways does anyone have recommendations for better alternatives?

The remaining income is then transferred monthly to your nominated bank account.

Am I reading correctly that it is abnormal to supply that information (As PDFs/XLS, not talking in a video) to a market-rate buyer? 

They also cap ACH transfers in at $5000/month, so if you're in a high-rent market you might not even be able to accept all your rents from a multi-family property through their system.

It's important to note that Detroit may have higher vacancy rates and lower demand, which could impact rental income and property values.

Interest rate, even if this is a cash deal?  

Good news is rates are starting to trend down and property values are still growing.The cash out can serve two puposes it can help pay off some high interest credit cards and be used for a down payment. 

Not sure what the going rate is.