The vegetation in between and even on top of the rocks should stay.
I can attest that Nature can find abodes for life even under the least hospitable circumstances. In my parents' garden I have a white gravel "basin" which is underlaid with two layers of plastic mulch. Still, given all these conditions, each spring I can see a few blades of grass growing up from, what is essentially, a few grains of dirt that occasionally drops in between the gravel.
Anyway, beautiful work René. No matter which decision you take, it's gonna be a cool pic.