I’d opt more for encumbrance being a factor over weight.
A sneaking movement type would help. I also once read a novel where the protagonist was a thief and he had shoes with especially thick rubber soles that helped him move quietly.
Thrown objects should create noise when they land as well, even if they aren’t particularly loud it would be something.
This is really all I have to add. I also skimmed through most of this thread so I may have missed something important.