I think the fairest way to do it would be to alter the canon and make the new characters graduates of the same graduating class as you guys. I don't want there to be any form of seniority or inferiority between the old members and the new folks (both in-story and out), as I don't really care for that kind of stuff. That means we'd be starting over again, though I do have a slightly different beginning prompt planned. At the same time, I'd also like to somehow feature the old characters in the story as well. I'm thinking they will become side characters who were sent along with the first invasion force while you guys (and the new characters) were left behind to later go on the missionary expedition. That way they'll still exist in the story in some form.