Play together long enough, and you will practically breathe in time with each other.
The ultimate flexibility is a three-piece band. The downside is that such a small outfit has a lot of holes in it's sound, which usually leads to a lot of sorry-ass lead guitar wanking.
I'd say you've hit on a wonderful combination, first time out! Multi-talented pllayers who cover a wide range of sounds. Once you get past the urge for everybody to play all the time (that means you too), you (as a band), can do just about anything.