I also have all of Henneth_Annun's messages backed up that were possible; sadly, numbers 1-16891 were inaccessible by all (no one can even see them on the site), but one of the members has several thousand early emails and is hopefully working on retrieving those in a form that can be archived. If you manage to get any of the early ones in some fashion, let me know! The numbers can be seen on the calendar, but clicking on them only brings up the February 12, 2003 (and after) messages rather than anything before that.

EDIT: I've also thought we need a list of locked groups - and not just of Tolkien, too. I've run into 10 so far that I can't get into and very much would like to, and they range from some Tolkien (though not on your lists anywhere!) to Pretender to L&O:SVU to Smallville to multifannish, for instance. Currently I have them open as tabs because I need to find a place to put them where they can be promoted. Perhaps a Google Form feeding into a spreadsheet as well? (And within the spreadsheet a link to "if you're a member, here's what you need to do!") I don't have the skills or time to create that, nor the social media accounts to spread it on, but if someone does create it, I'll put it out in the few places I can, and add the groups I know need backing up.