Toon Link will have to give it his all if he wishes to take a win and get closer to Link. Zelda is a powerful foe and her long range abilities can have devastating results. Luckily, Toon Link has his Mirror Shield, which should block anything short of a Light Arrow. Zelda can transform into Sheik and make this a tough hand to hand fight, but I believe that Toon Link takes the edge. He may not be big enough to engage in hand to hand combat, but his quickness gives him the edge in an all around fight. Toon Link wins.

Update. Hyrule Warriors allowed Zelda to really show off her power and I believe that she can now edge out Toon Link in a fight. Zelda wins.