Man o' man! Here's the deal - you're in a church with old people. As mean as that may sound - If they can even hear the drums, you're gonna get complaints from someone. That's just how it is, no matter how quiet they are. Been there, done that. I've had people tell me the drums are anti-religious.
Replace the sticks with drum rods (ya know - the sticks made of tiny thin sticks? Turn down the guitars, and make the vocals dominate the mix.
Good luck.