Finally, I had the time to check and recreate your suggestions. I've never tried to mix up noise oscillators with each other. It's so much fun! That orchestra atmo/drone is amazing. A really good idea to check it out later.
I tried to recreate the bass too, but I think I need more practice because it didn't sound okay. :D I have a Korg Opsix and I am trying to learn more of it, and it's so challenging but super fun!
Thank you for your super detailed description! It's good to hear you have time for your hobby. :) I never checked actually the person behind the Hyper Light Drifter OST, but I did, and this guy is really kind and has really great ideas on his youtube page.
Have a great day, take care!