To answer question two.
Yes they are the same type of question. And no it does not depend on the work in my view, but the artist as to whether you use "the singer is" or "the singer was." In this example, I'd suggest the singer WAS as MJ is no longer with us ( sadly). We can no longer refer to him as IS, even if it is a song on the radio playing now in the present day, as MJ.... no longer IS... even though his work IS still current he IS NOT= he WAS the singer.