I agree with the whole system thing. Some of these match-ups are not the sort you'd think one would see on a daily normal basis or consider in one's mind. I have an actual story idea kicking around based on the whole Harley/Snake Eyes thing alone!..but I might wait out the whole Cobra takes Gotham for a week more or so.
Current match at hand. While I'm sure I've both read and seen Voldy deflecting spells I'm not so certain he could so the same with a plasma bolt. Unless he's being given the Elder Wand as his most powerful incarnation. I'd wager items that essentially mess around fighting against death itself might just have a fail safe for something like plasma to happen to their controller.