Mass Effect 3: Citadel DLC FAQ

As BioWare gears up to release Mass Effect 3's Citadel DLC next week, they've taken it upon themselves to crank out a detailed FAQ to answer some of the burning questions fans have had since the final add-on was announced. I suppose you could consider this spoiler territory:
Will (CHARACTER NAME) be present only after a certain mission?

After completing the adventure portion of the Citadel DLC, you will have the chance to reconnect with old friends. Your friends will only appear once you have completed their content from the main game. For example, you will only be able to meet up with Jack after both completing Grissom Academy and talking to Jack in the bar at Purgatory.

Should I Have Everything Else in the Game Done Before Playing Citadel?

There is no right or wrong time to play the Citadel DLC, once it's unlocked. If you play the Citadel DLC with everything else unlocked (just before attacking Cronos Station), the new DLC content will all be unlocked. If you play the Citadel DLC right after stopping the Cerberus coup attempt, the DLC content will unlock naturally over the course of the main game.