There are no cheats for Halo 2, or for any halo so far.
halo 3 does not have any cheats
no cheats in any halo game
Well... yes. I would think so. I think the the way you would like to say that is "Do you know where I can find Halo 2 cheats?".
yes there is there are many cheats in halo
No
no
None of the Halo's have any 'real' cheats, the only one is the lower your weapon one, which is just like Halo 3's.
yes
no
The only things that would be counted as cheats in Halo 2 are the effects from the skulls when activated. More information on the Halo 2 Skulls is provided in the link below.
No cheats