You would think considering a lot of them use stealth they would emphasize it because their smell would give them away, right?

[[ There’s a difference between masking your scent and smelling like deodorant or expensive/scented shampoo/body wash. They’d still be giving themselves away with our types of hygiene. 

It was stated only that Kabuto was possible of erasing all traces of his presence from a scene, and I can assure you it wasn’t because he showered daily. ]]