They are making halo 4 right now as we speak because Bungie had a contract with 343 industries but Bungie quit it and sold all their halo's to 343 Industries therefore 343 Industries now owns all the Halo's and their making the future Halo's
Halo 4 is called Halo 4.
Halo rights are owned by Bungee. Technically Halo 4 is "Halo ODST"
Yes, there is a Halo 4.
There is multiplayer in halo 4
there is no halo 4 because it is a trilogy. halo 3 was the end of the series.
halo 4 limited edition, comes with a copy of halo 4, a T-shirt and special armor customization.
Masterchief
No, the Arbiter is not in Halo 4.
Halo 4
In the Halo Universe, Halo CE. In reality, Halo 4.
Not yet, but there will be. Well, technically, you could classify Halo: Reach as Halo 4, but as for the actual Halo 4, its currently in development by 343 Industries.
Halo 5 will most likely follow the story line of Halo 3/Halo 4.