The first question is guite interesting
I have been playing dom for long time and didn't know the answer yet. So i run quick test for it. If the commander who moves in magic phase don't have a place to retreat before normal moves and combats are resolved he will die. If other magic phase move clears a retreat way for him he will move there.
There are some spells that give fatigue to the target Stellar cardases and ghost grip for example. Many elemental damage spells also make fatigue damage as side effect. Thunderstrike for an example.