Without trolling through the pmdev wiki's going back I couldn't really tell you. I don't even remember if it was tye or vroom who added me to pmdev, (probably tye). I think I added ysth to pmdev (and maybe SiteDocClan) back in the day, and I've added a bunch of other users over the time, about the only other ones that I remember were adding castaway (i think) and corion (pretty sure) to Power Users.
Also, i recall that chromatic added xdg to pmdev.
I think you should get copies of the various wiki's and review them for usernames and announcements. Generally new users are announced by someone, which means you might be able to write some code to help you out, for instance blocks in the wiki that contain the first reference of a users name are likely to have been the announcement of their addition to the group. Most likely the author of the block will be the person who added them. Something like this is pretty useful as there are a fair number of wikis going back quite some time, and each one is 65k, so scanning it by eye is going to be annoying (i tried, and decided it wasnt worth it :-).
Actually, if you could get a copy of all the change records for the wikis your job would be a lot easier. You'd know exactly who added the new users name.
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$world=~s/war/peace/g
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