How do you get halo reach armor for your avatar offline?

Kats helmet is gotten from avenging a team mate is online matchmaking.

Juns helmet is getting 100 kills in firefight without dying.

Elimes helmet is gotten by getting a bulltrue medal in matchmaking.

Carters helmet is gotten by completing a mission on legendary without dying.

Jorges helmet is gotten by getting a killtacular medal on matchmaking

(7 kills within 4 seconds of each other)