I use Google camera since it is designed for the pixel phone and has all the neat functions. Along with it I use Google photos for gallery and editing, it's especially convenient since Google camera can only open pictures you just shot from their own app. Both have internet permission set to off and they only require Google service framework, which also has internet access off. So I don't see a need to use storage scopes, since they have no way to send telemetry back to Google (as far as I know). Only thing is you need to allow the apps internet access along with play services for a few seconds in order to get all the functions working, after that you can shut it off completely again. I used storage scopes while doing this, just to avoid anything being tracked.
About the buds I see no reason they wouldn't work, if their normal Bluetooth earphones. I haven't had any problems with neither of mine, Jabra and Sony.