Right Manipulator does not pose a threat by itself, but with the Proto fal'Cie enhancing and commanding the Manipulators they could become a nuisance. It is therefore recommended to get rid of them before focusing on the main boss.
The player should use an offensive paradigm like Relentless Assault (COM/RAV/RAV). There isn't exactly much help in debuffing them, given their low HP and stagger point. However, if they get to unleash their stronger attacks the player must get ready to change to a restorative paradigm.