No, the usb is given priority if it's on both. I know this for a fact.@MikaDubbz Sorry, didn't read the whole thread and am tired af.
@godreborn I don't think it's that simple: As Mika said the haxchi forwarders need to be in different titles. IIRC the Wii U will show the title on NAND only when both share the same title ID.