Difficult one because we're comparing chalk with cheese.You have in a sense to gauge by the changes brought about.
I voted for Newton, he changed the way humans regard the universe.He not only discovered the laws of motion and gravity, he did much work on light and invented calculus (Leibnitz is also credited with this but they both probably developed it independently) - he was also a major player in economic theory.Einstein used Newton's work and worked on from there.A genius true but some way behind Newton because Newton did his thinking in a world which believed in magic , supernatural intervention and superstition whereas Einstein was born in a scientific age.
As for music and the great composers-yes , the creativity,imagination and capability required to produce points to true genius.Samewith the great writers like Shakespeare whose achievements were simply staggering.
I don't rate Edison as being in the class of genius, he was a developer more than an inventor.He is commonly believed to have invented the light bulb though it had been patented 6 years before he was even born!The same with all his other "inventions" , the ground work was done by others.He was however a great marketer and publicist.
Tesla has been mentioned but again he was a developer of the highest calibre.He didn't invent AC electicity, that was done by Faraday (another candidate for genius status) but he did much to make it what it is today.Tesla himself said he had been inspired by Faraday's work.