When attempting the Inspire Formation action can the units being removed come from anywhere in the formation? In other words can the removed units come from the Reformation Area, or the Formation's Reserve, or do they have to come from a formation's battle waves? When attempting to Inspire a Formation it obviously makes sense to remove previously routed units as this reduces fatigue, does not reduce the number of deployed units and also saves having to rally the units in due course, but this is only possible if units in the Reformation Area can be taken. I cannot see anything in the rules that stipulates where removed units can come from so I have been assuming that they can come from anywhere, but it would be good to know if this is correct.
Yes, that is correct, you may remove them from anywhere. And it is both most realistic and most practical to remove a Unit from the Reformation Area.