Doubled vocals totally work. Quirky chords and arrangement, like the Dan were forced to play a set with the Beach Boys.
Mix-wise, the vocals could be a bit more forward, but honestly as I listen, everything seems pretty far back. I could have just pushed the volume up and it might have been fine. Are you thinking you might "master" this one later, or are you there yet?
a truly original work here - I liked the performances all the way through. I guess it all just could be louder. Sorry, that's not a very helpful "mix critique" :)
cheers,
-Tom