As far as doing older overdone songs again (such as anything from Les Mis, Astonishing, Defying Gravity, etc.), my advice would still be to stay away from them. The reason you want to avoid overdone songs is not so much because they're being done a ton at the current moment, but because casting directors have heard them hundreds of times before, which means as soon as you start singing, they're immediately thinking back to the last time they heard the song instead of focusing on your actual audition (just a natural psychological reaction that subconsciously they're going to start thinking about somewhere else they've heard it before). So even if they haven't heard On My Own at an audition for 10 years, odds are they've heard it many, many times before, which means they're that less invested and that less "in the moment" in your audition.