It depends on what difficulty you play on, Easy, Normal, Heroic or Legendary
No.
Halo reach online is easy and hard depending on how good you are and how good other players are
Yes, you do.
Yes. but it is hard to come buy you can also get it online but if you do find it dont get surpriced only halo CE and halo 2 is on the pc
Yes you can, but games like Halo 3 were made to work best with a hard drive.
well, that's a hard one. halo 4 will come directly after the events of halo 3 so, i would imagine so.
you can download halo 1 demo but usually hard to find cannot rerally download halo 2 or 3
hard-drive
No 'even a baby could do it
Inheritor, and it is VERY hard to get to.
NO, you need a flash drive for everything.
you can do it on normal, heroic, and legendary, but not easy