Yes
There is a night time +21 offering that isn't for children, but the daytime version is child friendly
The regular underground tour is all ages (and I believe there's a ghost hunting themed one that is as well). But the underWORLD tour is 21+ and your ticket gets you a free drink at the bar after.
Yes! I believe so.
Yes but on my tour an older gentleman couldn't keep up with all the walking. He had a cane, I would just keep that in consideration if your doing the tour.
Regular and ghost tour Yes.
Yup, my kids liked it
If your child isn't into history or architecture probably not. My ten year old referred to it as old stinky basements. Lost interest quickly even though he loves seattle. Smaller children would have a hard time with the many many stairs. You'll probably end up carrying them as no strollers allowed. Tour guides use "adult" themes and terms that go over children's heads.
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