My wife and I own an Interior/Architectural Design company.

Many big companies say "take it or leave it". 

I'd love to hear your experience so far with some of the other companies in the space! 

I think getting the water company out there makes the most sense which is what you are doing already do good luck. 

Who has a title company?

Should I be contacting expired listings on the MLS, foreclosed listings, distressed sellers etc … Also does anyone have recommendations on how to build relationships with banks, credit unions, investor-friendly title companies, contractors, appraisers etc?

These contractors can be on the pricey side you'd want to make sure the #s work before considering a reputable contractor.

While you may manage the building yourself, what impact would hiring a management company have on your returns?

I see investors who I have spoken with have issues with appraisals which heavily affect their loans, they have worked with certain companies that don't appraise correctly and even admit to it.

Alternative is to use an Auction company .