Very interesting thread, I'm looking forward for this game.
In a 9 min long trailer I can hear Your Rain from SH4 OSTs and a track called The Day of night from SH2 OST so this means there may be more of sucha 'flashbacks', like for instance SH1 ambiences also heard as Travis walks into the house. But from the trailer its hard to make a diffrence between added BGMs and originals. 8th probably was too excited with everything going on around her to remember each particular ambient sounds
From the SHF.co.uk board:
SHF: It's great to hear Akira Yamaoka will be composing the soundtrack. Is all the music to be original or will tracks from previous games be re-used? Is a soundtrack CD going to be released?
A soundtrack CD is planned at this point. All of the music created for Origins is brand new and original.