Gideon: Stun his BFFs after they activate and move themselves into position for the double attack from Master Stroke.
If you don't have access to Stun, force Gideon to withdraw asap. Unfortuantely that's really the only way to reign him in, once he has Mobile Tactician, he always has a free 4th action that he can use to mitigate strain or harmful conditions without slowing him down at all.