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Sure. Although the mating splines on some of the later cassette bodies are different, watch out for that. And that 10mm allen sleeve holding it on can be pretty damn tight... I have a WH-9000 which I tried to crack apart, to no avail, and that's with the allen key in a vise and me hauling on the wheel for all I'm worth. But I've undone probably half a dozen others, so it should be doable.
You'll need to sort out the OLD and dish, of course.
Can you easily replace a 7 speed freehub with an 8 speed or more freehub?
Like in this video.
https://youtu.be/V8Xnc6KrEqk?si=CouHMKraNfKqlBmI
I've seen a lot of conflicting write ups