That's my issue though. It being an ONI cover up makes absolutely ZERO sense considering the fact that the general population was aware of Chief being alive after the events of Halo 3 as depicted by Hunt the Truth. The only way Believe works is if after Halo 3 Chief just never came back.
You're not going to find a better explanation because the real reason is the creators didn't know H3's story. This is something that really requires a Doylist perspective, and a Watsonian one won't ever really make sense.
I think so. Installation 04 was redesigned in CEA then retconned out of it in H2A. I would imagine all the Halo rings would look the same on the outside. Unless this is Installation 07.
EDIT: Actually this must be I-07. Since the only rings the UNSC has stations around now are 05 and 07, and we already know exactly what 05 looks like.
That's quite likely, cool.
For those who aren't aware, Installation 07 is the only remaining ring from the original array of 12 Halos. These 12 original Halos were three times the size of the 6 made later. 07 was damaged and repaired itself by shrinking to match the new 6 in size, giving us the set of 7 we had until CE. Given this, it likely would look a bit different.