Maybe in the future, but not yet.
halo 3 odst, unlike halo 3, has no matchmaking, sorry
No they won't.
No, players will not be able to play as an Elite in mutliplayer mode in Halo 4. Confirmed by 343i.
To play on Halo 3 matchmaking you must have a gold xbox live membership and an internet connection to play on matchmaking. If you only have a silver membership it will not let you play matchmaking.
Most likely in Forge, Custom games and Matchmaking. Campaign? NO
No not unless you were banned from Xbox live all together.
yup
It's a rank.
Matchmaking
Yes. Halo 3 and Halo: Reach both have Matchmaking.
play in matchmaking
Shoot and kill people.