Group Composition & Custom Companions

For my first full play-through (my first attempt ended in Defiance Bay due to lack of satisfaction) I will make my main character a Cipher. After that, however, I was going to add a custom made Barbarian for two-handed/pike use and a Rogue I intended for ranged combat. Since these companions will not be entering into any conversations or need to match my personal preference for race and background, I was wondering if anyone had a suggestion for how I should arrange the stats and talents of my new Barbarian and Rogue to maximize their potential.

I was also wondering what would be the best party composition going throughout the game? 

My Final Party should look something like this:

Tanks: Paladin + Fighter (Pallegina + Eder)

DPS M: Barbarian

DPS R: Rogue + Cipher

Support: Priest (Durance)

But I don't know if the Barbarian is optimal or if the Priest is necessary. Can a Druid substitute for a Priest for instance?

I am hoping for a set of guidelines I can reference going forward so I never have another case of buyers remorse. I hope the community can help me on this matter.