@Winterstar well, if you're planing to install GApps, you should make a clean installation.
But if you, like me, just want to use the latest LineageOS without waiting for the microG port, then it will mostly work.
Things will be less integrated, but will work nonetheless. I ended up doing a clean installation of LineageOS and installing the microG bits manually.
Now all the boxes in the self-check screen are marked. I was hoping to fix some problems, but this procedure didn't fix them [1].