I like the idea of operating it like a small scale hotel as @Bobby Lee mentioned.

Like someone else mentioned, doing a short term rental in a secluded basement that is very private and walled off is one thing, but sharing the same refrigerator, kitchen thermostat, etc. with a complete stranger seems like it will introduce more problems than what the money is actually worth.

Also depends on what you mean by modest income and bad credit....Worst case like someone else mentioned, you could stay in this property and buy the next with a DSCR.

I second what everyone else has mentioned...

I'm going to get a survey regardless, but I'd like to line all this up before I start spending on soft costs.The weird thing is I see other investors doing these DADU deals and I've never heard anything mention the above requirements / scenario. 

You mentioned not having a good ROI with them?

The letters and post cards are coming to my personal address but they don’t mention the property in question.

Just mentioning Columbus is going to bring your DMs to the brink of melting down.Ask yourself why real estate?

There they have a much higher likelihood to get tenants who will pay not to mention respect the property and make things easier for everyone. 

I will look into the options you mentioned and factor in all the informative insights you shared.