Phasma + FOO + kylo + ? + ?

If you're low to mid level you should farm FOTP and FOST. It's a slow and grindy farm, but believe me. It's worth it. I started FOTP as soon as I could (since I got lucky and got him in a Chromioum back then) and the other FO characters little after that. I got bored of the grind and stopped farming FOST and FOTP. Now after their reworks, I regret doing that. That team is great for every aspect of the game. Good damage in both Raids (specially normal and Heroic AAT), can solo GW, Top Arena team (with at least Kylo and Phasma zeta you can beat any Sith team out there) and Offense mods challenge, which are needed if you want to make a team with Darth Nihilus lead in the future.
If still you don't want to farm them then you could go Leia, Boba or TFP instead of FOTP and Fives, B2, Sun Fac or RG instead of FOST.