Building a four plex from the ground up

[Von Sevilla]

From getting city permits, to underground sewage lines and construction, what's the avg cost of building from scratch? Also looking to have built in washer/dryer in each unit and installing solar for the entire building. Based on numbers for those who own duplexes what's the avg ROI? I plan to keep this building forever, use it as passive income and pass down to my kids. I can do minor work, electrical, and some plumbing.