Here's the timeline I've got (last updated just before the refugee realms opened up):
December 2, 2015: Announcement
December 5: New realms are fully set up and ready to accept immigrants
December 12: Elections start
December 15: Enforcement of character limits, Closing of Atamara and the Far East Island, Elections complete
December 21: Implementation of additional realm size modifiers, and other fixes/features
December 27: Restrictions removed, realms cut loose
January 15: AT/FEI access removed.
It's not set in stone; I'm open to some changes if there's a good reason for them.
