For Seattle, my experience is that most of the people are there for tech work. Those folks could have been working anywhere from "just came to this city" or "have been working for 10+ years".
There's not that many tourists, the few ones that come visit mostly congregate in pike place and around the space needle.
Ehh not exactly. Yes infant mortality would skew the data a bit, but modern medicine, along with modern agriculture has definitely increased the average life expectancy by a sizable portion.
Nowadays, people don't have to worry about food stockpiles and periods of shortages. Malnutrition was definitely a big issue back then. Especially with things like baby food being present, which was a big factor in reducing baby death rates
Modern medicine such as vaccines, surgeries, supplements, and even basic hygiene has made wonders for the average health of a person. Things that would normally kill a person, like bacteria infecting a wound, nowadays is mostly recoverable and minor.
If you look back even just a century, life expectancy was a lot lower than the present. https://www.statista.com/statistics/1040079/life-expectancy-united-states-all-time/