Yup, you'd get 2 Death Shots, and Opportunist applies to all attacks against activated characters. Whether the attacks are generated by a CE (Death Shots or extra attack with Leia or Bothan Noble), an AoO, or just taking a shot on your own turn, Opportunist/Cunning/etc. apply to all attacks.
You would also get abilities like Twin Attack on both Death Shots. A fun squad has Plo Koon, Mon Mothma, one or two Czerka Scientists, and a bunch of the new Spaarti Clone Troopers, plus Yularen. They get 4 attacks when they get killed, with Opportunist!
swinefeld is also correct in that the +10 damage from Mon Mothma would only apply to the attack SHE granted (so you would have to specify before you make the shot whether it's the one granted by Mothma or the one granted by Plo Koon). If you got Twin Attack with Mothma, though, you only get +10 damage on the first, not the Twin.
EDIT: Double ninja'd!
