Great advice for moving forward, but assuming all those Rebels are somewhat geared, they might help you out now.
Jyn lead with Leia, K2, Cassian, and Biggs, or Ackbar lead with Jyn, Leia, Biggs, K2.
Also, on the early nodes you can swap in people from those Rebel teams, making sure they end the node with specials not on cooldown, so they have turn meter preloaded. Use your other team to go through the other nodes, then for node 12, use your relatively untouched Rebels team with preloaded turn meter.