please do not put the heat rock in, your crested could burn its toes on it. how old is the crested gecko you are getting? Do you have a thermometer? Without knowing what temperature it is in your tank with your bulbs, no one can tell you if it is ok. It depends what temperature the room is in which you are putting your tank. Also, DO NOT use orchid bark. Crested geckos are clumsy eaters, if it grabs a piece of bark along with the cricket, it could swallow it and die. The waterfalls tend to be a haven for bacteria because they are tough to keep clean. I would therefore not recommend one. You should be able to achieve the correct humidities (above 50% most of the time, and between 80-100% for a couple of hours per day (i.e. after you spray them).
please have a look on google for some care sheets, or pm me and i can point you towards some more information.
The kind of setup you need really depends to a large extent on how bug/old the crested gecko you are buying is.