Hornwort... we have it floating at the top, almost covering the majority of the top. The owner of our lfs says it's recommended for most cichlids, and even gave us a couple of bundles for free to get us started(he's been in the hobby for 30+yrs and obviously is real nice).
The majority of our african cichlids are mbuna, and they use it to hide out and the fry love to hide at the top of it if there are no more hidding spaces at the bottom of the tank.
Doesnt really require special/extra lighting, therefore will grow nicely, but not too fast. But can be messy sometimes with some of the pieces falling to the bottom that die off... but all in all it is well worth it.
Depending on the set up, I'm not too sure about java moss. With it being so light weight they might stir it up too much, so it wouldnt attach to anything really, and they might even eat it. So that would be a risk, but if you find otherwise, let us know, cuz I'd love to put some in to have some plants at the bottom for the fry to hide in too.
Tricia