Is it possible to view or change other user's preferences from an administrator role?

I don’t think so

You can set General Preferences at Setup > Company > General Preferences, where you can also preclude users from setting their own options for certain settings. You can also define certain preferences at the role level on the Preferences tab in the role. You can also set some preferences by assigning dashboards to the roles and checking the override existing user's settings box, but I think it's just the same options as the actual settings on the role, but maybe there's more you can do that way. Haven't played with dashboards in a while.

but even still, I don’t think you can do things like set

POPUP SEARCH USES KEYWORDS

for everyone (which is something I always have to tell new employees to tick under their Preferences)

Yeah, there are a bunch of things you still can't do, which is annoying. Just user training at that point, unfortunately.

Thanks to both of you - I figured as much but wanted to make sure.