I made an upgrade from 14.1 with magisc 16.0 as root and systemless xposed.
after the recognition of a stupid error in the process (i forgot to disable xposed for nugat in magisc manager before updating -> that produced a bootloop) everything went quite well.
i formatet the system partition and installed in twrp lineage, gapps & magisc in one batch and the phone booted in about 4-5 Min.
At first it seems that everything was working as before, alle the former data was there, but then i recognized that there are some issues with installing (xposed) “unknown” apps. (new oreo settings were set for xposed manager) even installing via adb install wasnt possible…
All that wasn’t the case with the lineage root module.
I’m not sure but it seems that there issues with magisc and oreo on some roms. On XDA is a explanation what is maybe wrong here: https://forum.xda-developers.com/showpost.php?p=76265320&postcount=1615
Conclusion: Magisc (16.0 stable or 16.7 beta) + Lineage offical build from 20180813 are not usable at the moment.