Is Gandalf more powerful than Majora's Mask? Don't think so. OniLink works plenty good against the mask, the helix sword itself is magical, as is the Master Sword. Plus Link has light arrows and such.
I'm stocking Link with 4 blue potions, not green ones. Blue is full health and magic... Hehe, my healing>yours. I'd also assume that Aragorn would drain his invulnerability that much faster if he kept healing stuff.
And Aragorn isn't getting up from being stepped on by a Giant who's a couple hundred feet tall. Neither are Gimli and Legolas, unless Aragorn now has an infinite supply of resurrection spells. For that matter, none of them are getting up from being hit by a dude who tosses big slabs of rock around. Gandalf can survive all he wants after he gets backhanded 20 miles away. I'm assuming that killing him like the Balrog did counts as a win, even if he comes back.