We got one at MSB in Dec. when we were there and they had changed them to be the same as the ones at Gaston's Tavern - it's actually a caramel topping and the typical sugar icing both drizzled on top.
No. The Boardwalk Bakery should have a temporary tent outside, And the other parks have all sorts of pastries, sweet rolls and such everywhere. There's the Writer's Stop or Starring Rolls for all sorts of sweets, but I don't know offhand if one or the other carries cinnamon rolls specifically. The Kusafiri Coffee and Pastry shop in Harambe (Africa) at Animal Kingdom should have them.