1. If you already own TDB and HoW, you can buy TTK for $40 from the Xbox Marketplace. Then on September 15th the addition Digital Content will be available as a separate purchase for $20. There's no link yet because the item does not yet exist. Note the $40 version is only available on accounts that own TDB and HoW. 2. Affect how? Nothing should change, no. Your characters will still be there regardless of whether you use a disk or a download of Destiny. 3. See #1.