Now I can add text to my avatar? Sweet! How do I do it?
When the end of game is triggered, it says that play continues until the last player.
Presumably, if the last player is the one to trigger this, then play ends immediately?
Yes, this is correct. The only purpose of the first player marker is to help the players remember who went first so that they know who goes last. Essentially, you finish the round after the game end is triggered and, as you stated, if the last player in the round triggers game end, it is over immediately after his turn is finished.