OK, I believe the old rule was if you Masterminded Damage to a nearby character with Impervious, say Darkseid, he COULD NOT roll to avoid this since he was NOT the original target of the attack. Now, with the upgrade Impervious has recently received, does Darkseid now get the chance to roll to reduce the Damage to 0 if say Dr Doom Masterminded it to him?

"Now" is actually October 15th, when the new rules become the tournament standard, but otherwise you're correct.