Thank you! Brass can be tough for sure, especially when mixing. French Horns especially have a lot of mud in their lower register.
What's funny is that I haven't watched 'Princess Mononoke' yet and consequently haven't heard the soundtrack haha. Just listened to 'The Legend of Ashitaka' though and can definitely hear the resemblance. I learned about quartal harmony from Hisaishi's work (particularly 'Spirited Away'), he loves that sound and so do I.