At this point I didn't really plan on micing the drums being the places we'd play are to small to really notice the effect that it would do. I was thinking about just running 4 mics for vocals.
Right now I'm looking at this mixer: Behringer XENYX X1832USB USB Mixer with Effects | Musician's Friend
Its got 6 mic inputs from future growth, its got the built in effects, it has a 9 band eq, and it has sub outs for future growth and use.
I am use to a mixer much like this, I use to run sound at my church and they had one similar except it had i believe 20 channels, and I really liked the ease of use of it.
As far as cooperation I believe it is there, we have practiced a couple times with out a pa system and we worked it out so we could hear each other and not drowning each other out