First off, good luck with the live set!
You probably won't need the compressor from the mixer to the PA as the house should have that already.
I'd definiately grab a mixer somewhere if I was you though. Having access to your own EQs would be helpfull, plus having the outputs of your gear on different sliders will make life easy.
About the drums. Here's where a sampler would be nice. It would be better to have played around with all the compression on the drums at home in your studio then record the result to sampler for easy processing later. If you are using heaps of different drum types in your set it could become a problem.
Anyway have fun and at least it's a good excuse to buy more stuff!