Frontlines isn't really an issue since gear is synched even on live, and it can simply be slightly modified to put people into any of the three teams, disregarding GC affiliation on live. The same could pretty easily be done for the dungeons, synching gear down as necessary (and presumably we'll be at max gear level for a non-50 dungeon in any event!)
We'll have to see - it's more that it is the sort of extra touch I won't put past the dev team at this point. They obviously like doing neat things for the players, and "oh look it's your character, tied to your badge or somesuch" is the sort of thing they'd do to be fancier than other events of this sort.
But even in this case, the answer to the initial question holds true: we will not need our security tokens at the event in any form whatsoever. We will not be logging into the live data centers to play at the Fanfest events - everything will absolutely be on an exclusive server set up just for the event (and possibly even in the same building!)