To get LineageOS on Rock64 working, it would take great efforts and probably a single person cannot do it alone. Would need at least 3 people contributing to the project as Rockchip has modified almost every important AOSP Module. I tried by just merging Rockchip's AOSP Base with LineageOS (CM14.1), first of all, there were huge conflicts, secondly, compile-time errors were uncountable.
https://github.com/Rock64-Lineage
Here is my failed attempt.
https://github.com/Rock64-Lineage
Here is my failed attempt.