I take it back, I don't know what to tell you other then this sounds like a bad idea especially since destiny should fix the problems with the story and other stuff that are already existing before adding more fluff
After rereading everything you wrote I'm noticing that the amount of stuff you have in yours is more than everything that's in the game including future dlcs, in other words, you have whole game which could be destiny 2. Much too big to be considered a dlc. I would just call it destiny 2
No just read what destiny is coming out with, there is already the 3rd and final subclasses for each character so there is no more open slots, bungivision can't release more then 2strikes and one or two mission per dlc because the maps are already on the disc. So the only thing that is feasible is armor and some weapons, read what they are putting out and cut stuff out of what you got cause its too much for them to do, be realistic and make it relate more to the game
Take off the tail, add a cloak or another class item, lose the sword and crossbow and add a gun, this is the future, antique weapons like that are no better then "no land beyond", do something that relates to the game not another lost story among countless others in destiny