It would be neat for them to appear as a pair, since they have jedi abilities and are twins,
- They could complementing each other in the likes of IG-88 does,
or
- Maybe giving themselves bonus when they are at distance 1-2 like one extra dice in offese (jaina) and defense (jacen).
or
- Copy each other's actions as a free actions at distance 1 (ie, jacen gets focus, jaina gets a free focus action)
The counter could be separate them with blockers, stress or ion.
We also need some more jedi-ish abilities in the game besides changing dice results! Like,
jedi mind trick: switch the dial to another of the same speed
trust the force: action: ignore stress inducing this round