That location looks GREAT!!
those balls on the ceiling are lanterns i think. they are going to look really awesome in some bokeh
im not sure, but i think the dj will probably be set up by the glass at the dance floor. if you have a lightstand, stick your off camera flash over there next to the dj and aim it into the center of the dance floor set to a wide angle.
i shoot with bare and direct off camera flash all the time, and i love it. for off camera lighting, you dont really need to diffuse it (IMO) because the shadows arent going to be harshly outlining everything. instead, they are going to be falling off to the side and where you can see them, they will be providing contour and depth.
IMO the reflector/assistant/offcamera flash would be combersome.
here is an example of my off camera flash. this is pretty much uneditted and its far from perfect..... it is just so that you get the point.
i see some terrible image compression/artifacting on this version...dont worry about that. also, i noticed that the thumbnail isnt coming up every time. if you dont see it, just hit F5 (refresh your page)
in all, that looks like an awesome venue. if you have off camera flash going, you will have some really nice pics provided you know how to shoot....
have fun
dont forget to eat when the time is right!