No worries, there's no stupid questions! I did change almost everything in the pack, so I can understand if there's some confusion.
I can make some gray cliffs in the new style and add them back in, no problem.
The way cliffs and grass work now is that grass no longer overhangs cliff edges, meaning I don't need to add every grass colour to every cliff. You can see from this screenshot how it works:
I probably won't make new versions of most of the floor tiles, but you can find all of the old assets in the "World of Solaria Rural Village Legacy Assets" folder.
Some of my Patreon member have already been using the new pack for a while, and the older assets mix and match pretty well with the new stuff!