It might not be a very Halloween-inspired release, but the soundtrack to the upcoming Halo 5: Guardians will be releasing via Microsoft on October 30th. Currently, the album is up for pre-order on Amazon in both a 2-disk CD as well a a 2-vinyl LP for $24.98 each, and will also presumably be released in digital formats around the same time.
Halo 5: Guardians is composed by Kazuma Jinnouchi, who also worked on Halo 4 alongside Neil Davidge, and was also a composer for Metal Gear Solid 4: Guns of the Patriots.
Check out sample of the soundtrack from MathChief’s second channel.