In the timeline, it says 'among others' when referring to the younger team, because I knew there were others who are considered part of that group, but I didn't feel the need to specify, seeing as the 'taken' page lists everyone who is part of the team as 'X-MEN' and those who aren't part of the team as 'CONSTITUENTS'. I suppose I could break it down even more so - elder X-Men and younger X-Men, but they're all the same in Charles' eyes. ;)
As for adding to the timeline, it's only there so we know what was going on when. If an event happened near something that was mentioned, and we've seen the films, then we know where it goes, lol. There's plenty that's left out. It's just there so we know what year we're in and how much time has elapsed, it's not there to show what happened before now, because I think we all have a pretty good idea.
I'm going to be keeping track of threads, though, with the location, date and individuals involved, so we can keep track of things current and backdated, both.