If you run double tanks then no, on the contrary. Def up is quite helpful and will give your main tank a chance to soak up some dmg. On that lvl stun is not too reliable, but buffs always help. His stun is mostly for when opponent has 2 units left. Your main focus is to get everybody else killed asap. Attacking Dooku will only stall you. Give him a potency cross and all else into health. You should focus on moding both tanks first and foremost since there are your lifeline. It will always help to have ackbar faster than Lando if you intend to use DD twice - you can easily whipe out opponents as early as round 2 this way - 3 DD attacks + single target.
Do take notice that there is always RNG involved. If you're unlcuky, epsecially on low levels, you will loose even with good set-up's.