I notice no one's mentioning Stormtrooper Han as the 5th. I'm in almost exactly the same situation as the OP and I've been running STH as the 5th. Chewbacca puts Guard on both Hans so STH finally becomes a viable tank for me. Between his taunt and R2's smokescreen, Rolo/Chewie are free to wail away---not to mention CLS doing his thing.
Since adding Chewie (and STH for that matter), I went from around 500-700 on my shard to around 150-200. I'm not mentioning that to impress anyone---everyone's shard is different and mine is probably pretty weak---but it's a frame of reference.
I do have Chaze available to me, but at the moment I'd rather keep R2 in the mix. Someone suggested using Bistan and that sounds like a great idea with all the extra attacks for Chewie, so I'm going to work on getting him geared up so I can play with that.
You can view my team here: https://swgoh.gg/p/299856229/