If a Martial Initiator like a Harbinger or Stalker were to multiclass into Barbarian for rage, would they still be able to use martial maneuvers?
From the PoW rulebook: "Concentration is not required to initiate a stance or maneuver, as with spells or psionic powers."
So yeah, you're good.
If you need more proof, there's a Barbarian archetype (Primal Disciple) that gets some Maneuvers, and no special ability that calls out they would otherwise not be able to use them while Raging. They lose all their Rage Powers for it though.
thanks..