Regarding ship arena, I am quite successful in a nearly whale-free shard (I could maintain #1 for 4 weeks now) with the following F2P setup:
Ackbar (G8), Biggs (G10), Wedge (G10), Boba (G10), TFP (G8), JC (G8)
Reinforcement: Maul (G8), Ashoka (G8) and Sun Fac (G10)
Wiggs and Boba and in my and Raws case Sun Fac is also part of your arena team for quite some time. Ackbar is nice to have for GW and rancor P1, TFP is useful for tank raid, Ashoka and JC may be used for defense mod challenges so all in all no gear got wasted here.
General strategy:
Constantly apply target lock with Boba, Biggs and TFP will lead to an endless refresh of Biggs shield. JC provides additional survivability of Biggs. If anyone dies, reinforce with Maul and start snowballing.
Kill order:
If possible, snipe out an opposing target lock applier that is squishy (e.g. Vader) or enemy Ashoka since she will hard counter your Maul reinforcement due to her ability reset. If not possible head directly for enemy Biggs. Do not attack enemy TFP since if you are as lucky as I am, you will get him evade 5 attacks in a row and feed the enemy capital ship like crazy.
Variations:
The only time I ever change my lineup is when I am up against Mace or I know my enemy has a Maul as first reinforcement. In this case I switch JC for Ashoka to dispell taunt / retribution.
So you see I do not go double-tank, since I have made the experience that it is more effective to instantly kill an enemy ship and force the opponent to fight an uphill battle. I would love to have FOTFP instead of JC to get even more target locks but since he is hard to farm I do not consider switching anytime soon.