If you haven't read this yet, you definitely should from top to bottom.
Lionfish Captive Care
For experts, it can be successful to snip the minimum requirements a little bit. For new aquarists, it can be an easy recipe for disaster, most often for the fish. Bioload wise, this will just about max out your tank when full grown, which leaves no room for tankmates. The dwarves are not very active, and this could also get boring fairly quickly. I would opt for fish better sized to fit in a 12"x24" tank that would make the tank seem much more active than its small size.