I think I'd look at Renton before Everett. Or somewhere east of the city. Not sure on housing costs, but maybe look at Sammamish Plateau or Snoqualmie (the town, not the mtn pass). Or maybe even North Bend, which is farther east, quieter. Or Covington? If you only need to come to town once a week, maybe also look west of Seattle -- Port Orchard comes to mind, and I have heard that Bremerton, a navy town with a transient military population, is improving -- and commute by ferry, which is really common, and easy. Bainbridge Island is probably not in your budget, but look anyway, as it's closest via ferry and I'm no real estate agent.
Seattle has a really serious problem with drug use and homelessness, but I don't think that should be an issue. I'm not fearing for my life when I go downtown. That's not to say it hasn't impacted the city, but it's not exactly dystopian, either.
I think the most important thing is, how do you and your family feel about the weather and lack of sunlight? Sunset is around 4:30 in winter. It's a myth that it rains all the time -- the reality is, it's gray, wet (but not often pouring), often raw, and dark, with a low, gray sky, from Oct thru March or beyond, and the joke is that the first day of summer is July 5 because it has often rained for the 4th. You have to learn to not cancel E36 M3 cuz the weather sucks. Guy I know, who moved away, used to call winter here The Long, Dark Tunnel; it's pretty apt, IMO. Summers are amazing, tho.
Meanwhile, while it may be true that people are leaving, I sure as hell can't tell. There are so many more people here that I get texts from WSDOT midday almost every summer Sunday to let me know about stop-and-go traffic on westbound I-90, *80* miles from the city as all the weekend adventurers come home. On Memorial Day weekend, backups began 110 miles out. In winter, the ski areas are also jammed up on weekends, if you're into that -- there are two that I won't go to anymore because the traffic is so bad.