Alpha Site has one which is found on the wall near the sniper, immediately in front of the left side spawn.
Windward also has a shotgun on the NW wall in the SW corner. You'll see a black box on the wall, the shotgun is mounted there.
ODST does'nt have the AR.
muythic map pack. that comes with HALO 3: ODST
Yep.
you cant
Yes.
You cannot make your own maps in Halo: ODST, it doesn't contain forge world. Halo 3, Halo: Reach and Halo 4 all contain forge world.
you can't make a firefight map using forge, only mutiplayer
Yes. There are at least two more. One is Halo 3: ODST, which is an FPS starring and ODST (it will also come with every multiplayer map from Halo 3.) The second is Halo: Reach, which nobody knows much about. Look for a preview in ODST.
On Kilowani Station. Which is the final clue.
i am VERY sorry to inform you of this, but you cant. in halo 3, halo reach, and halo 3: complete multiplayer experience you can.
yes only multiplayer has the new map packs but you can get them in the DLC
All of the maps, including The Mythic map pack 1 and 2, come on the Halo 3: Mythic disk that is included with ODST. If you don't want to buy ODST, I believe that the full Mythic maps are available on Xbox Live marketplace.