Do units block LOS and Movement, especially friendly units? Can artillery shoot over friendly units?
Units cannot move through another unit unless in skirmish formation, so one formation of column cannot move through a block or line formation (for example).
Friendly units can fire through friendly units, cannot fire through enemy units to enemies further away. Artillery can shoot over friendly units.
I've made comment in the battle of Teddysburg section as to another idea (elevation levels), until this is discussed I think we can stick to the above mentioned, just for ease.
What happens if a panicked/broken unit flees into a non-panicked/broken unit?
A fleeing unit will always try to get past the non-panicked unit by going around. If it cannot and must go through the non-panicked unit, this causes the non-panicked unit to need to make a normal test.
A panicked unit cannot end its movement inside another formation and must continue to move till it is at least a half inch away from the back end of the formation that it moved through.
What if a unit charges through a panicked foe using an order?
Combat begins again with the panicked unit, it now fights at the panicked base number of 9, it receives the -1 to armour (saves on 6) and +2 to their breaking point. So basically they will fight badly and most likely run at the end of the combat again, potentially they will be destroyed.
What happens if you charge into two separate units?
I think the easiest way to do this is to divide the number of attacks based off how the bases line up against each other.