They explain it in the article. Someone, often the funeral director filling out the death certificate, asks what the deceased did for most of their working life.

I’m a little skeptical of the category “ambulance drivers; not emergency medical technicians” as reliably coded, because people will often say so-and-so “drove an ambulance” when they were actually an EMT or paramedic. But it’s also not clear to me that would invalidate the findings.

I think this is an Apple bug.

I’ve seen it with non-Google apps too. I’m not sure what causes it, but I believe sometimes you can long tap the link and select the correct option.

I believe the behavior where you say no and it still tries to open the app is because the default behavior on Google Maps links is to open Google Maps.