First off, soap in streams and lakes is a big pet peeve of mine. Absolutely, no washing with soap anywhere the residue could potentially flow into streams or lakes. This could be 100 feet away or 300+ feet away- pay attention to drainage.

I would not worry about unscented or not. Unless you are out for a long time, all your clothing and you will have residual soap smells and you will always have small residual food smells on you. The small bit of soap you use to wash hands is not a big factor.

I take the Dove dry-foaming makeup removers. There is very little soap in each cloth (I cut them in half and only use one half per day). I wash hands and face at night so I do not smell like a fish. I feel that smelling like scented soap is better than smelling like food. The wipes are scented so they go inside the bear canister at night.