By getting halo 3 odst ( two discs ) first disc halo 3 odst campaign and 2nd disc halo 3 mythic comes with all the halo 3 maps.
It is not on a disc! It is on the sheet that says Halo Reach, But you will need Xbox Live.
get a new halo 3 disc
Yes.
Yes
Yes, The Pit is a map that comes on disc for Halo 3.
it is for messing around if your normal halo 3 gets damaged.
No
yes, unless you want to play halo 3 mythic which comes with ODST
yes, but its only multiplayer as in against each other
You have to put in the Mythic disc, then its the same way as Halo 3.
yes