Again using a similar approach as Vangelis, layering many synths over the keyboard with different velocity and key zones, and several midi filters (maxforlive devices hosted in Ableton Live) that allow, for instance, to play the flute sounds only with the upper key pressed, or the low strings with only the lowest key pressed. No sequencing involved.
Get the wav file here: https://drive.google.com/open?id=140KGnhFhza-WTf5ZkMjXAM57Z81MOU4Q
source