I remember going to the editor's room in Skyrim and looking into Misc. Items cabinet. I was just skimming through it when I saw dragon heartscales after the dragon scales. Now, I don't have the Dragonborn DLC installed, or any other DLC for that matter. So were the people who made this game really thinking about putting these into the game?
Kahvozein's fang is in a random majestic chest (the huge one at the end of a dungeon with the most and highest level spoils) in one of the many ancient Nordic ruins. I think it's random, but I know I found it more oftenly in the ruins west of Solitude. So you can either go blindly hunting around, or get alteration to level 90 and take the quest from Tolfdir where the quest marker will point straight to the fang.