Interesting questions, there is nothing in the Clash of Eagles supplement to exclude Landwehr from having a sub-commander. With regard to rally orders, it is interesting that there are two types of order that require the general to be within 12 inches of the unit, Rally and Follow Me. Of these the supplement only mentions Follow Me, so my assumption is that the intention of the author is that sub-commanders can’t issue rally orders. The supplement positions sub-commanders as a way of extending the command reach of brigade generals without penalty, in that sense they are similar to the marauder special order. It would be interesting to understand the authors thinking.
Having said that I use sub-commanders in some of my scenarios and tend to allow them Rally orders as this is more useful than follow me. I also think that allowing blunders to only apply to the sub-commander is very generous.
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