ST han VS Leia VS Admiral Ackbar

I'd go with Leia. She can hit up to three times per turn and can grant critical chance up to allies

Ackbar heals and dispels.. which are nice. Also, as a Fleet Commander may help with challenges in the future?

I think, STH is the best F2P Tank and therefore I suggest playing him.

I'd go with Leia or STHan if you can get a lot of speed mods for him.

Different topic but, I feel like Sun Fac laughs at all of the STH's in battle. IMO he's the best FTP tank. Though I haven't seen many rebel teams with him. Sun Fac vs AOE team like the rebels just crushes STH's taunt and makes him pretty useless in comparison to the rest of his team.

I've heard you love Zam Wesell so i would go with her for your fifth spot

I recently replaced sth with Leia and I'm super happy, especially on raids. But... I already had k2 and pathfinder, so I was heavy on tanks. But if you want offense Leia is definitely the way to go.