So I found out today that LineageOS 15.1 has started rolling out builds to some devices. Here's a link to the article and which devices are first in line! The shamu isn't on the list, but will hopefully be coming soon!
Link: https://www.androidpolice.com/2018/...nounced-android-8-1-base-customizable-colors/
Link: https://www.androidpolice.com/2018/...nounced-android-8-1-base-customizable-colors/