I'm currently running a 4/5 Rebel team with Ackbar lead: AA, Luke, St Han, Biggs, FOTP. All L76-78, gear VIII-IX with gear X on Luke and Omega on Luke and Ackbar basics. Currently building up HR Scout to round out the team. I generally place around 25 when I'm done climbing the ladder, have no problems until I start running into Rey, RG, QGJ teams.
For me, St Han is indispensable. TM gain vs Dooku and/or Fives is excellent. The speed increase from Ackbar is great so he gets the taunt early, and 3 turns is generally plenty to make the difference. He often doesn't survive through the whole period, so it doesn't matter that his turns go by faster.
QGJ can be a problem. Rebels get a number of passive buffs, so QGJ is likely to buff up his team at some point unless you take him out. So generally target him first and wait to taunt until he is gone. If there is a higher threat (Rey), I will try to eliminate her first which usually means offense up for the rest of his team. If RG is there and stops you from finishing Rey, hold your breath.
As far as assist attacks go, Biggs or Luke theoretically get 67% of those and I can live with that. When HR Scout is ready, 75% of assists should be someone other than Han. You should be able to live with those odds. Besides, Han can deal considerable damage, sometimes. As it plays, it seems like Luke gets the assist more often than not, which is fine by me.
