I have two problems. They are both visible in the gif.
1.) The Sculpt level 0 shape/silhouette hardly resembles the Sculpt level 1 silhouette. I doubt I can bake a good normal map to level 0 if the silhouette is so different. Is that supposed to be that way or can it be avoided?
2.) After I did some sculpting on different multires levels I begin to have stray vertices coming out from the mesh in some places, only visible on certain multires levels. If I smooth them back in then it messes up the other levels (then the other multires level show strange vertices too), if I smooth them back in then I get the same issue on the other multires level again. Anyone know why that is?
Edit: Q1 was solved by MrZaks tip to click "apply base" and the stray vertices Q2 were gone when I cleaned up the topology inside the mouth.