It all goes well until brunch, when I get tons of errors about missing manifest xml's. I can browse to the folder where the xml file should be (the folder exists) but the folder is empty. Where am I supposed to get them??

EDIT: to be clear, this device has been dropped from LOS support. I have an installation zip and got the proprietary blobs tho...

Have you followed the build guide of the device?
For the vendor files you usually need https://gitlab.com/the-muppets, when not extracting them manually. Also, take a look at https://luk1337.github.io/muppets/ on how to add them.

Thanks, that's just what I needed! Apparently LOS can't publish the muppets step because it violates intellectual property rights or something.