1. If I control the Magneto that says at the start of the attack step he can exhaust a character of level 4 or less, my opponent controls Gambit and I exhaust him can he use Gambit's effect in a chain to stun a character if I have initiative?

2. If your front row caracter becomes stunned and you have an exhausted support row character can I attack your endurance points directly if those are the only two characters you have or do they both need to be stunned?