Nobody has a crystal ball and knows what the future holds, but if you want to introduce a partner/sell ownership interest its far easier if the property was originally owned as an LLC rather than in your personal name because selling membership interest in an LLC is far simpler than re-titling real estate. 

A super ball number to get you going would be at least $190/SF-$220/sf ish... to figure out square footage it's probably best to connect with a Chicago architect like @Samuel Pavlovcik or @Prashanth Mahakali both can talk through the zoning and plan development process.

You have the passion, but you want to find some connections in real life or start the ball rolling here and take that to a meetup.

I like to share this story as a cautionary tale and while nobody has a crystal ball and can predict the future, understanding the end goal can  help investors understand  whether they invested in a market that can reap the true benefits of SFH rental ownership or perhaps point them in that direction. 

Along with what's already been said, I would use a professional photographer to really showcase the spaces so Guest can envision themselves playing bocce ball, lounging outside, etc. 

Since you mentioned that your area lacks nicer/unique short-term rentals (STRs), this could indeed be a golden opportunity.

The golden goose has been terminated and those with true value will win, those who only believe they add value will be looking for the next guaranteed check. 

We also don't know the exact numbers of your prospective rental investment (including taxes, insurance, PM fees, etc.).Once you know all of those things, calculating this shouldn't be a huge task.If I had to ballpark it you'd be cash flowing perhaps $800-$1,000/month on the duplex given the rental amounts you ball parked.

FOs like me now are playing ball, we weren't this aggressive 20 years ago. 

If my rents stabilize -- The portfolio is golden.