First blush is that since a USB sound device like a Focusrite or M-Audio require driver installation that it wouldn't work, as you can't install drivers on an Android device. It may be that some supernerd somewhere has written a driver for Linux, which is at the core of Android, but that may be a chore to find that supernerd. And then talk him out of his software!
Looking at how much heart and soul you have invested to set the tablet up, would it be worth your while to pick up a laptop (they are REALLY so inexpensive now) and move those songs to a laptop? As a "Pay it forward" kind of thing I have a no longer used M-Audio Fast Track Pro interface I would just give you for the shipping charges. It would give you 1/4" outs to go to your mixer.
EDIT: This reply should have been pointed at Uncle Paul but somehow got referred to Mountainside.