by Weltenreiter
Yes, only draw for units you have (since you draw 1 card per unit).Yes, as soon as they happen.
Yes, generally owner assigns unless otherwise noted.
You CAN move thourgh activated areas, just not out of nor activate again. Activation is more of an "these guys have already gone" marker in systems where turn-analogues take long enough that marking it is useful. As long as the guys you actually move have not already gone, someone else having already gone doesn't hinder them.
Not sure on order, new rulebook streamlined that order some and ironed out some kinks, double check. Generally it would count its strength first, and only later flip, when doing consequences of the battle.
Yes, Siege Tower Orbs stack. Or Orbs in general. Resolve each.