(Now, given that there were 20 people who came through and nobody rented initially is a different story, but regardless...)I'd suggest a pro photographer (or just look at pro photos and do your best to get close with a real camera, not an iphone), also, keep in mind what's in the photos.

When I got home I downloaded my camera and and started to populate a basic info spreadsheet I built to document my findings.

Give them some gloves and headgear and setup the camera! 

Being the squeaky wheel by calling the police as well as installing security cameras, even fake ones, is a great idea.

If you need to locate the lateral, Dept of Public Utilities can tell you where it goes and can also camera the line for you for free, but it takes a while to get them out there.You can PM me and I might be able to get you some contacts for the City.Some suggestions of people you might use for this:Stemmle plumbing for PlumbingWhaley Excavations for digging in the streetsPryor hauling for digging as well.

Cameras.  

My main camera died and I had to use my iphone :/ so it came out a little different than in person. 

For the inspection bring a friend, the bigger the better, and a video camera.

Thank goodness there was a camera in the parking lot.

Cast iron pipe is old, and unfortunately that's just the way it is.I would talk to your plumber who did the work and pay for a camera down that pipe.