All of the Light Side Hard Nodes I was able to 3 star my first time through running the same team. Needless to say, it helped having an Ally maxed GK offered to help me do it, but none the less I can honestly say I did not use a single Zeta character in the line up.
Ally GK Max G11
Barriss Lead G10
QGJ G11
JKA G11
Ahsoka G10
Aayla G11
Like I said, the GK helped a lot ( taunt, foresight, crit imun ) but so did Barriss as the Jedi lead. Added HP from her lead, health regen at the start of each character turn, and ofc she cleansed as well ^^
Good luck, although I can not offer a GK to you, I can offer you the Barriss lead, PM me and I will kick you the Ally code.