It looks like you may have buried the rhizomes of java ferns. That may be why they are not doing well. Lift them up or tie them to driftwood.
I noticed this as well. Some things in your tank were ideas I had of doing in some of mine. I like it. Get those ferns out of the substrate and you should be good. Are you dosing ferts? With mosses I would avoid Excel, but have you thought about C02?