There are a limited number of combinations for the origin story, class, and race. For instance, the human class can only see the Noble or Circle of Magi origin story and Dwarves can only be Warriors or Rogues but not Mages. I have listed all possible combinations below:
Human -> Mage -> Magi
Human -> Warrior -> Human Noble
Human -> Rogue -> Human Noble
Elf -> Mage -> Magi
Elf -> Warrior -> City Elf
Elf -> Warrior -> Dalish Elf
Elf -> Rogue -> City Elf
Elf -> Rogue -> Dalish Elf
Dwarf -> Warrior -> Dwarf Commoner
Dwarf -> Warrior -> Dwarf Noble
Dwarf -> Rogue -> Dwarf Commoner
Dwarf -> Rogue -> Noble
As for the DLC, certain vendors included unique items such as weapons and armor, which are good, but not THAT great. However, the DLC missions ARE worth getting as one missions gives you what is now my favorite companion, and the other gives you access to the best armor/weaponsmith in the game (not including the unique armor you can get from Wade if you do the scale quests).
Well I'm not sure how much of the game I had completed but I know it was real early in the game. But I had a random encounter where the crater appeared and I picked up some meteor rock and took it to the armorer who fashioned it into Starfang.