If you mean like a care package then it requires Hardline Pro.
The emergency airdrop killstreak is unlocked at 8 kills.
You cant
No.
you can unlock it with you're first killstreak award unlock
you change your kill streaks before or after thegame.
you can change your gun camo and your camo on your person.
the violence settings can be changed
Change Your Perk3
The call of duty world at war is not a prequel to call of duty black opst.
call of duty black ops
it is called call of duty black ops.
not unless you're in spectator mode