Everything unlocked?

Is there anybody that has played Reach since launch and has absolutely everything unlocked in the armory? I’ve been playing it since around 2012-14 and my armory is still not complete to this day, it may say 100% but that’s not the case, there are still a few things I’m missing and they are: Red and Blue flaming helmets effect, Officer elite class, special pre-order chestpiece (UA/Multi-threat)

Actually, tons of people have. If you go over people in your party or in matchmaking, it’ll say ‘Amor Completion’ and a percentage. Lots of people are at 100%, including myself. You can have it at 100% WAY before reaching Inheritor, I think at the rank of Eclipse.
There’s a couple of others things you need to do to get 100%, finish the campaign, get a few achievements, do some stuff on Halo Waypoint, but all of that is pretty simple.
Then finally there’s the ‘Haunted Helmet’, which is unlocked at Inheritor (though you are already at 100%), the helmet with Blue Flames (which is currently unobtainable, and very few people have it), and the helmet with Gold Flames (included in Legendary Edition, you could still buy that but it’ll be expensive).

Getting 100% Commendations is much, much harder.

It’s faitly common to run into people with a 100%. Wouldn’t be surprised if a few were modded however.

But reaching Eclipse isn’t that hard. I bet there’s tens of thousands of people with that rank or higher.

I rarely play anymore but every game I’m in, someone has 100% armory completion. That’s easy - as a previous person said you can get 100% at eclipse. As for the extras you mentioned, those are either much harder(read:expensive) to obtain or just plain impossible like the blue flames effect. I’m still peeved at GameStop as I preordered there and was supposed to get a code for multi-threat and elite officer but did not, And at the time all I wanted to do was go home and play the game so I didn’t make a big deal about it. There are also a lot of modded accounts too with 100%\100% armory\commendations but they are easily outed by their low ranks or fully onyx max commendations with not enough kills to warrant that in their service record.