The two we're adding are Kenshi, who players will recognize from previous MK games, and more excitingly we're adding Scarlet. Anyone who knows the history of Mortal Kombat will tell you that back in the days of the arcade - when they did just palette swap characters to come up with multiple fighters in the game - there was a glitch in one of the old arcade machines that caused the Jade/Katana/Milena female ninja to glitch and turn red. People always thought it was a hidden unlockable character and it wasn't, it was purely a programming glitch. They've always speculated and in fact it was the fans who named her Scarlet to begin with. She's no longer a glitch - she's an actual character, and she'll be coming pretty soon post-launch."
They won't be copy and pasted from characters already in the game - they're going to have their own unique fighting styles, moves, fatalities and x-rays - all the good stuff