It was included in the film as an homage to Steven Spielberg for all that he has done for Lucas. And since it is in the movie, they are canon. While it was probably not intended to be so (Lucas promised Spielberg that he would include E.T. in his next film, since he included Yoda in E.T.), it has by default become canon. The race has become known as the Children of the Green Planet
. The name of their planet is Brodo Asogi
, and the representative in the senate was named Senator Grebleips
(Spielberg spelled backwards).
On to E.T. being Force sensitive, probably. He may have been a padawan of the ship (he seemed to be as much a child as Eliot was). They really haven't delved into the background, only aluded to it.