It matters how you mod it, if you just get a mod from "Modio" then you would be using the account that you moved to your computer, it just matters what account your using. If its a online or offline account. If your not familiar with Modio you should it up. Its a great program!
You can in HALO 1 if you use mods, but it has to be on the computer.
If You Mean change into elite, no, you can only do that in Halo 2, 3 and Halo Reach. But however you can use mods at halomods.com
use modio to put the mod on the xbox, but you will get banned so i dont recommend it unless its for an offline account
You are not able to at all without the use of mods.
Free offline mods are available in many places. You might want to try Simtropolis. There are many mods there and I personally use some of them.
You can download mods for Halo:Reach from se7ensins.com so long as you have a way of transferring them on to your Xbox, such as a data transfer cable or a USB memory stick, this may get you banned if you use mods online. If you need any more help there are many tutorials on how to mod it on se7ensins.com
In halo reach,You can not use cheat codes.nor in any halo game
sorry but other than mods you can't "cheat". you can use as many guides and tips as you like!
You can't unless you use mods.
yes ,because halo reach is the last halo game,therefore,it would have to be used
No.
You can't get Halo on PC