[why changed the assault rifle in Halo CEA?]

I think they're just placeholders.

[Halo 4 trailer: Notice the missing codpiece?]

Cryo Wood.

[Game Engine]

It's more than likely going to have a new engine, all the Halo games were made using a different in house engine (except for Halo: Custom Edition).

[Halo CE Remake confirmed. But will there be forge?]

I believe it is going to be an ODST type deal, Campaign on one disk, Multiplayer on the other.

[So... about this "Secret Helmet".]

saying its impossible to get new armor into the game because of coding and stuff.

It is possible, but impractical, doing that would require downloading the game again with the new armor in it. Over 9 Gigabytes of data. But, there is the possibility of DLC (Disk Locked Content) for completing some requirement. Not even hackers/modders can get into Disk Locked Content.

[Can you play online on Halo 2?]

Only on PC, but you need a good connection.

[Master Chief"s Cod piece]

My guess........... CryoWood.

[Forge!!!]

I believe there is going to be an ODST set up, with Reach's multiplayer on a separate disk.

[Renovate halo: CE]

The funny thing is, 343 has been working on it for a while now.

[Halo 2 Online support.]

Original XBox LIve was shut down completely, but with the demand, I think me MIGHT see a Halo 2 anniversary around 2014 maybe. Like with Halo Combat Evolved Anniversary.

[Halo 2 PC]

I have it, but I won't send you a friend request.