Is there a quick way to make all bones in a rig use Euler Rotation rather than Quaternions?
Run this script with rig object selected in in pose (or object) mode, changes all rotations to 'XYZ' euler. Change the order to suit.
import bpy order = 'XYZ' context = bpy.context rig_object = context.active_object for pb in rig_object.pose.bones: pb.rotation_mode = order
If you have an action check out this answer