“SNL” is having a banner season, both in comedy and in music. Fleet Foxes, the indie Seattle folk-rock band which is scheduled to perform on Saturday’s show (hosted by Rosario Dawson), is another inspired choice. The Foxes, known for their gorgeous harmonies and radiant music, saw their self-titled debut album make several prestigious 2008 top ten lists. It belongs in your music library. The band will perform “Blue Ridge Mountains” and “Mykonos” on “SNL.”