I have found the (most) music that played during the Atriox trailer. The beginning plays a mix of two different parts from the HALO 5 song “Dominion”.
0:00-0:59 and 3:10-3:53
If you put those parts together they sound almost identical to the Atriox trailer. The second part of the music is in another HALO 5 song called “Crossed Paths”.
1:49-2:22