You've been putting a lot of thoughts into that! I just happen to know the basics of Akira Yamaoka's composition thought processes, the harmonic choices he likes doing with chords, form, structure as well as how to recreate those ethereal, dream-like pads with layered SFX for both the calm and horror parts. Whenever you're ready, If you'd like, I could compose a free 2min sample to see if you like it!