As far as I understand it, you succeeded in ordering the brigade to move.
Page 38 of the Rule book deals with Moving Chargers from Brigades
As far as who can charge and can't, it sounds like you did it correctly in that units are moved individually and into correct melee formation. The last two units can be moved into supporting positions behind or to the side (if movement allows) of the combat units but must also be touching each other to form a smaller brigade. In your example, the last two units that did not charge can move forward, provide support for the combat as long as they are touching each other at the end of the movement.