I think Bungie deliberately made the challenges to get the helmets for your avatar as a symbol of each of Noble Team’s characters.
Carter: Carter was very hard to understand and but I think I got it. Carter’s award is to survive a legendary mission without dying. Carter, being part of Alpha Company is almost as lucky as John 117 for surviving and so that is where he got his award from.
Kat: Kat’s award is to avenge someone’s death in matchmaking. Kat saw Thom die and he didn’t feel to thrilled when Six joined the squad, this means with every Covenant she killed she thought that she was avenging Thom.
Jun: Jun’s is to kill 100 enemies without dying in campaign and firefight. Jun survived the longest without dying in Noble Team.
Emile: Emile’s is to get a bulltrue in matchmaking, the first Zealot Emile kills in his death scene would have probably earned him a bulltrue medal.
Jorge: Lastly Jorge,s is to earn a Killtacular. When Jorge blew up the Covenant ship I think he did get more than a killtacular but it still stands as a multikill.
So do you think that these are the reasons for why they implemented these specific challenges to earn each Spartan’s helmet.