You should not judge Ackbar too early. Pull Scimitar out of the reinforcements and laugh about the counterattacks totally wrecking the enemy while your ship keeps getting protection up. So much fun!
(Who would be your 5th rebel for the EP Event in March?)
Mace seems to be better with more republican ships, so does Rex. If you go Mace, you would probably change you setup accordingly. One guy in my guild uses a clone team, that is three strong republican pilots. But we have Wiggs instead, and rebels synergise with Ackbar.
JC in cantina?. Cantina energy is valuable because some toons can only be farmed there. Think of Wedge, TFP, Aayla, B2 and GS, while JC has hard nodes too.
But if you just need some quick 30 shards, not much is lost. On the long run, bronzium pulls will also provide you with a couple of JC shards.