The idea of a full album of Everly Brothers covers by Will Oldham and Dawn McCarthy (of Faun Fables, and Oldham’s collaborator on 2006’s The Letting Go ), seems strange enough on its own. The quirkiness of What the Brothers Sang, then, is only augmented by the duo’s choice of cuts: almost all of the material here comes from the Brothers’ late-1960s period, and steers clear of their familiar late-’50s hits. Oldham and McCarthy’s affection for these songs, however, borders on the reverential: They don’t use the obscure originals as raw material for their own creative explorations, but rather carry out largely faithful covers that feel more like homage than anything else. The end result is an album that feels something like a campfire sing-along (even if most…