Brake pads question

Hey,

I installed new WH-R501 wheels with Claris brake pads, and I am not sure if everything is OK.

Is this normal that even after short trip brake pads are covered with thin "aluminium gray" coat? Something like metallic mist on surface.

I also found some metal fillings in brake pads, and few very small surface looses on rim. Is this normal in new wheels?

I picked up metal fillings, cleaned brake pads and rims, but during braking I still can hear quiet noise. Maybe brake pads are too hard?