Even though the Final Fantasy 7 Remake may reuse some of the main themes from the original game, it sadly won’t have the same composer.
The original Final Fantasy 7 composer, Nobuo Uematsu, revealed in a new interview with Jeuxvvideo (via NovaCrystallis) that he won’t be returning to compose the remake. His response was “not at all” when asked if he will be back.
Since the game is a remake, it will utilize many of the old themes Uematsu created back in 1997. They have orchestras that play the Final Fantasy 7 themes all the time and that would sound great in itself.
Advent Children used some of the original themes as well as having some new music of its own. The animated CG movie was composed by Nobuo Uematsu, Keiji Kawamori, Kenichiro Fukui, and Tsuyoshi Sekito.
As for the PSP release Crisis Core, that game was composed by Takeharu Ishimoto. Ishimoto also used some of the music from the original Final Fantasy 7, but also added a few arrangements of his own. Ishimoto also composed Final Fantasy: Type-0 HD.
Hopefully the new composer who will be working on the Final Fantasy 7 Remake pays tribute to the original music while adding some new songs that captures the scenes of the game perfectly.