You need to post a thread showing off all of your toys in depthI think you should function as a sub-mixer sending signal to the main PA on your own. Then you eliminate any kind of confusion as to how to wire everything up.
If you can swing it, find yourself a Mackie 1402 VLZ, which gives you six XLR inputs just for you (and it also has a few channels that take 1/4"), but six is a good number. Then get enough Shure SM57's to cover the drums, and one good mic for an overhead, like a AKG SE33B. That should fill up six, right? Then just send one cable from you to the main PA and mix away from there.
I have a Mackie 1604 VLZ3 I can use just for me, or as a main PA console since it has 16-channels of XLR, 8 direct outs, 8 aux sends, 4 busses, - it definitely gives me a lot of options. But I play a 4-piece kit, so I have options to mic all the drums with a couple of overheads, or just the bass, snare, and an overhead, or...etc.,... If you're talking making the investment, doing it once is a good idea. Get as big a console as you can afford (or want), and just let it give you as many options as you can get. It should be at least somewhat "almost upper-end" because the circuitry will just be better and clean. Some of those old style "brain" mixers use inferior electronics and just make a lot of noise.
The neat thing is that I managed to find the console I have for only $250 used on eBay. Of course, there's a certain amount of risk there making sure what you buy actually works, but I have access to people who can test and fix the stuff, and I've been lucky meeting honest sellers so far.