So my understanding of the Special rule is that the Mori are the 3 RED units on the baseline on the Left, and the Chosokabe are the 2 RED units on the baseline on the Right.
Some BGG questions and my answers
boardgamegeek.com/thread/2671510/scenario-37-special-rules
a) move, but are moved along the baseline, or pushed back onto the baseline? My view is once released, they stay released, but their passivity might be rectivated by a setback
A1: Once released, stays released
b) are attacked on the baseline before being activated? Do they become active? If not, can they battleback?
A2: If attacked may battle back, but are not released
c) the wording of the rule is a bit cryptic, "given an order to move off the baseline" , so can they be given an order to combat, or to move along the baseline?
A3: Can be ordered to battle normally, but not move at all. The no movement restriction is primarily to keep the Command card release instructions sensible.
d) May the Mori and Chosokabe leaders be ordered to detach from their units and move independently to join/support allied units?
A4: Yes, with an Order 1 card.