Freedom of speech is freedom from oppression from the government. The French government in no way oppressed Charlie. They are still putting out papers. However, freedom of speech is not the same as protection from retaliation. Killing those guys was murder, but if some nut job is going to kill you for something you said, it does not matter if you had a protected right to say it, you are still dead.
He absolutely reinvented the light bulb. http://en.wikipedia.org/wiki/Henry_Woodward_(inventor) The only invention of note that he actually did himself was the phonograph, which admittedly had its' own impact. Edison took existing inventions from a staff , like Nikola Tesla, who worked under him and commercialized them. He was a good, even visionary, business man, like Jobs, not an amazing inventor like George Washington Carver or Nikola Tesla.