To the third question: Local superiority of troop numbers lowers your enemies morale. So does having exposed flanks. So generally, you want your strongest units on the flanks so they won't be scared, and maybe a unit or two in reserve to cover the main line's flanks as well. Missile units falling back behind the line can also work here.

Obviously killing a unit causes a loss of morale as well. If you can kill 5-6 men in one second with a jav volley (or 10 with volleys from two units) and pull of a simultaneous flanking maneuver, there are many units that will simply cut and run at this point.