Misa

With Misa's blue skill, does she have to move through an enemy hero? Does the ";" make moving through an enemy hero mandatory?

No. They are connected statements, but not the same. If it was mandatory, the wording would be something like "Move up to 4 spaces in a straight line ignoring obstacles through an enemy hero, ...."

Can Misa's two blue cards discard or place enemy units while moving through smoke grenades?

There's no yes or no answer, since it depends on positioning. The move part doesn't care about the smoke bomb as long as it ignores obstacles. Then you get to the discard/reposition part of the text and check the smoke bomb position relative to you and the target. So the key is smoke bomb's effect is checked _after_ Misa moved.

1. With Min's main red, can he move if the target he hit dies? 2. With Misa's silver, can she use the heavy for the jump, since it doesn't target it?

I don't know. It's a another channel question, not another channel question.