in the Mixer reverb and chorus don't seem to work

Hi

I have a piano, flute, strings, brass and drums orchestrated. When I adjust the reverb and chorus, I don't hear a difference. I am using Melow piano, expressive strings, etc. is it possible these instruments come with their own presets and will not respond to further adjustments?

Regarding panning, left pan is heard in my right ear and visa versa. I checked, my left ear bud is in my right ear. So unless my brain is circuited differently, I'm not sure why that is.