After three coats of cement I decided to go ahead and paint. I went to Tokyu Hands to get some acrylic paints. One of the employees recommended 'Tamiya' brand. I used black, white, brown, and flat green to get the results seen in the picture. I'm pretty happy with how the rock turned out.
I used black silicone in all of the holes and the water tank at the top of the waterfall. I am also going to coat everything below the waterline with eboxy. I think it should be waterproof.
The 100 yen shop had a bunch of epiphytes so I bought some. They should work well on the bark I'll be adding.