Bring more Characters in from past Halo games

I think it would be really cool to bring in people from past halo games.
The Rookies ODST squad
Spartans from all the books
Arbby
ISO-Didact
Mention something about Noble team

Another thing I would like is to kill off Sarah Palmer… I just don’t like how she disrespects the chief in halo 4. I feel like she thinks that shes soo much better than MC.
Let me know what you guys think and about other characters you guys would like to see back in the game or out of the game.

I think do to it being a new trilogy, I think only some characters will return, not all of them.