I've found a lossless version of the digital-only soundtrack for Higanjima, but unfortunately it's not available in my region (NA):
https://ototoy.jp/_/default/p/401429

Would someone be able to help out with this? It would help make my archive for Hiroyuki Sawano's work be completely lossless.

Hi !!

You can find all the music Sawano has composed from 2005 to 2015 here, and the whole score from Higanjima is available free there on download ;-)

http://anime-soundtrack.diary.ru/p183518453.htm?oam