I made them play instruments just because
then I made headcannons about it idk

Roy wanted to try to play an instrument
He did get familiar with a cello but the bowing was hard for him so Ross suggested and electric guitar
And uh
Ross plays multiple instruments bcs he's cool like that
But he does like the electric guitar more since his dad taught him how to play it
Oh and Robert doesn't play an instrument
this is nothing close to being canon cough cough

so uh yeah how silly