I'm lacking a network and relationships with like-minded people.

It's paid for and the people across the street offered me $1800 to rent for her mother and brother.

I’m seeing people seeing an issue with what might be a disability.  

Also what do people recommend for remodeling?

Areas that have been good 30 or 50 years ago are still good today.One wildcard though.The city of MKE has initiated a projected called GrowMilwaukee, which is based on the majors vision to increase population (for fiscal reasons, more people per square mile) and they have identified the lack of midrise mixed use districts - they call it the "missing middle".

I have been researching on how to start the process of investing and I’ve talked to a few people who are more knowledgeable than me in real estate.

Often, people like me surf several different jobs/careers, only to find themselves in their thirties without a vocation--something they can find truly fulfilling as well as profitable.

Does anyone know of any people who have successfully navigated building an ADU on their property locally? 

When times get tough, people downsize. 

But with enough work and connecting with the right people you can make it happen.