I've been looking at some small multi family homes on the MLS in Chicago and it seems like a lot of the rents on there are below market.

Will they also provide filters for specific markets: Short Sale, Off Market Distressed Property, For Sale By Owner...etc?

By renting to them at ~$10k below market annually, you are essentially writing them a check for $10k each year. 

You can always give them a slightly below market rate for being good tenants/friends, however, you are placing a lot more risk on this property financially if you are $800 under market value. 

Do you think it will be lower in 4.5 years?

The property is in Stoughton WI, no improvements were made and leases are below market due to previous landlord.

Could anyone help find any mistakes or missing pieces below ?  

So, if he's been there several years I'd ask for an inspection during business hours, maybe change the furnace filter or something. 

My needs are few, and they're relatively simple, but they're not the kind of thing I've seen mentioned in the filters of any real estate searches.

I won't invest in anything below 10% ROI.