While testing how Xenforo imports the content, I noticed I had accidentally duplicated a lot of the content, is there a way to remove ALL content that is not default (Back to the install) without reinstalling?
I would like to be able to wipe for example all users, but NOT all data, whereas other times be able to wipe all data that was imported.
You should import into a new installation of XF. Use your test forum as a point of reference in manually applying any custom development to the final import, as opposed to building onto your test forum and taking it live. There is no easy way to deal with the duplicate content if you import again into the same forum.