Unarmored Defense (Barbarian plus sorcerer plus monk) [duplicate]


If there is a level 3 Draconic Bloodline Sorcerer, with a level in Barbarian for Unarmored Defense, and another level in Monk, for a 5th level character in total, would their total AC be 13 + CON + DEX + WIS? What if this character was also a warforged, with +1 to AC, +2 to Constitution, and +1 to Intelligence, Strength, or Dexterity?

Could a 5th level character do that in the first place? If so, does Unarmored Defense stack in that way?