I'm an architect and work in a firm that is in downtown Wenatchee. 

If you have an architect friend, it'd also be a good idea to buy a vacant lot and build a creative cabin-style home.

I follow the STR rules because I'm an architect as well as an investor....so it goes hand in hand with my profession but I don't have any STRs, only LTR. 

As an Architect I also use the AIA contracts, on all my projects, regardless of size. 

It sounds like you are looking for a residential (1 - 4 unit) property and not what the finance industry would consider a multi.To attract an experienced partner, you must bring something of value into the partnership - capital, experience, a deal, an applicable skill (i.e. architect, electrician, etc).  

Unfortunately, the building code book is complex and designers (architect and engineers) are corrected on there designs all of the time.

You should hire an Architect with the right experience.

I'm building an ADU from scratch with an architect on a hillside.

Whether they'd like the addition completed demolished and removed or if they'd like an architect to draw plans and make some changes.

@Juan Sanchez - I've personally never dealt with the Illinois Municipal Department, but definitely reach out to @Prashanth Mahakali or @Samuel Pavlovcik both are architects who deal with the city of Chicago on a regular basis.