Third Shadow Gate
I hate to say it but Link would lose.
1. No matter how many items Link has he wouldnt be able to counter Sora's magic attacks.
2. Link's attacks are mainly swords n bombs- tactics dont change
3. Sora is able to level up and adapt to fights
4. Sora has a posse
If you really hated to say it, you would have bothered to research your ideas a bit more carefully.
1. Nayru's Love, Magic Cape, Cane of Byrna. 3 items that make him invincible, effectively countering the magic attacks. Combine that with any number of spells/items that effect all enemies in visible range and are unavoidable...
2. Um. Please point out to me any Legend of Zelda game where the tactics never change. And I'll point out to you every other Legend of Zelda game where you're forced to constantly change your tactics to include the item or items you acquired recently if you just want to move on past the dungeon you're in.
3. Link is able to gain more health and adapt to fights. Your point?
4. Sora is alone. If you think Sora's friends are a fair addition to the fight, then I'd say Link gets Midna. Who lifted a bridge with her mind and wrestled Ganon, a gigantic pig-demon, to the ground. AND can open pathways to the Twilight Realm, in which Sora would be transformed into another creature.