MemoryProfiler: zero RefCount

Yes. These are, however, also things to look at regarding potential memory leaks.
Now, they might be about to get cleaned out by the next Resources.UnloadUnusedAssets swipe, or within the next 1 or two scene unloads (Assets attached to scenes stick around after the scene is unloaded until the next one is unloaded). Something worth to investigate for you. Diffing snapshot before and after such unload operations should allow you to see, if this is getting removed as expected.
Seeing as this is a ScriptableObject, which you might have forgotten to call Object.Destroy() on so maybe the managed wrapper has since been GC collected, but the native memory still lingers. Similar issues tend to blind side people when using RenderTextures.

General Advice: Remember to Call Destroy on UnityEngine.Objects that you created yourself.

 

Yes, also, because you may be loading a scene after the current one is unloaded, that reuses the same asset. loading and unloading the asset then results in needles loading time.

That said, if you don't care for that optimization because most of the assets are unique and you're more worried about raising the high water mark of your memory usage, you can load an empty scene in between and/or call Resoruces.UnloadUnusedAssets in between of scene loads and take the unnecessary load time hit for any assets that might be present in both scenes.