Starting with a 13 health Vader is not bad when you can Leadership and Price of Failure for amazing damage potential. Instead of Boundless Ambition I included As You Command and Force Strike to fix the dice after reactivation. Ciena and Vader should also produce enough resources for Rise Again plays.
Other cards I am considering: Become One for some crazy resource generation or damage increase, Imperial HQ to further reduce the pay side pain. Unyielding or Intimidate for shield hate, Resilient, Endurance - if people are planning to throw a ton of removal at Vader, this is the answer.
Other partner to consider for this setup: Nute Gunray - one less health, slightly worse die for resources but a focus side instead of a Ciena´s modified side (essentially a blank). So sounds like a better deal? I´m not sure - Ciena´s one more health can be crucial for surviving long enough for Leadership and Price of Failure plays. You could be starting with a 6 health Nute which could turn off 6 cards in your deck a bit too soon.