. * I do get why other realtors on here are asking you to lean on your current realtors : bc if you bring these strategies to them (knowing that they did not proposed anything like this) they won't have the teams to suggest to you (ie contractors, architects, drafters, and navigating the permit process with building and safety with the city). 

ADUs are the new buzz word, but are highly overrated.If you really want to continue, I would pay a local architect to sit down and talk it over with.

You'll first need to hire an architect to design the unit.

They have an in house architect.

I am an architect who uses generative design to streamline the production of mid-size projects but I am not a full-on programmer.

@Michael D Valadez - Congrats on getting your 2 flat rehabbed, that's awesome and I am sure it was a ton of work.Tons of great advice above, but I'd suggest the first you do is talk to a local Chicago licensed architect like @Prashanth Mahakali or @Samuel Pavlovcik. 

The architect and the engineer are working through the changes. 

The builder may also have a relationship with a bank for construction loans.We hired a great architect as well.  

Craig's list and eBay over time DIY (who knows).....Upscale heavily decorated costs money.In many cases DIY can save about 50% in labor, but high end unique things will require workers with specialized (more costly) skills.To get the Look you want, the best way to accomplish a tied together "Feeling" is to get with an 'Interior Decorator" or Architect who does this style, and bounce the cost questions off of that person.There is no way to tell....is the animal skin bead spread $30 from a yard sale or $3,000 at Nordstrom's carpet department in Seattle?

Put you architect hat on or find a student architect to challenge him.Spanish style center courtyard, walled exterior?