All material aspects can be layered, but there are much easier ways of doing it.
One of the main things is to just do one bit of layering and then pipe that into a MakeMaterialAttributes, before going onto another area. In this way you can work on each section separately rather than ending up with an enormous blend, which I think you’re heading for.
I think this vid covers what you’re interested in, but if not there are a couple of other vids he’s done about good ways to blend layers:
PS: He covers a good way of doing puddles near the end.