The original question was "can you run all these on one controller" - the answer is YES!
Since it is a club, and I assume there is a bit of a budget, I say go with the most control. A Show Designer may be overkill if there are no plans to expand but an Operator is a great unit too. In addition, in a club you often play to relatively the same crowd. Variety is important! Get a real controller and design some looks and shows for your club!! Also, nobody should buy 3 dimmer packs for 12 lights!!!! At least two lights can go to each channel and, if the wattage in those par 36's isn't too much, you can probably run three to a channel.
One question, are you sure those par 36's are "par" lights and not pin spots???? Many pins are in par 36 cans (but you can get a base and a 120V flood into a par 36 size can). Pins would require a relay pack not a dimmer pack.