Cad is good against DN lead. I use him to have a 2nd stun if ability block doesnt proc on DN or vader or to kill dooku quickly without to worry his counters and heal under DN...other than that he is just not much of a big deal...sometimes also good against yoda, ackbar or rex to just prevent them to ten-up one more turn or clearing the debuffs.
I played long time with greedo but his terminal bombs are mostly just a waste of a turn and the 2x attack when crit is all about RNG too. Zam terminals are enough usually and not too painful if dispelled.
Dengar atleast has a powerful stun and alot of life and protection. B2 is good again chaze teams and make it easy against rebels in general....my thought about geo soldier and sun fac is that sun fac can dispell buffs has alot of health like dengar but also counter and taunt. Geo soldier has an assist that can 1 shot an attacker toon with the other BHs in that setup and he is fast.
Another problem is that if i use 5 BH i drop on def like hell while with b2 and and dengar i wont. Maybe they are a better def combo or i just dont get targeted so much cuz b2 is a pain to play against sometimes.
Boba, zam, ig88, geo soldier, sun fac would give me
2x dispell, 2x abillity block, healing immunity, terminal bombs, taunt, assist, dmg over time and so on...just cant try it out cuz my geos are low stars.