I kept a figure 8 puffer in freshwater for a long time with no problem. as for light, those T5 lights will grow the plants fine. I'll let everyone else knock you for the 70W MH idea. You'll need it three feet above the tank, and at that point, it will be more of a room light. With either light, CO2 and fertilizers are a very good choice.
The rock cave is cool, but do make sure to secure the pieces together with silicone or some non-toxic epoxy.