yes it would work. you need to move the dlc OFF the usb stick though, I wouldn’t recommend (and don’t even think it is possible) to try to edit it while it’s still in the xbox-formatted usb stick.
just make sure you select “CON” and click sign and rebuild when you’re done.
now, make sure when you put it back in the usb stick that you do NOT put it back where you got it from. when you put dlc to the usb stick, it goes in a 000002 folder, customs go in 000001, so make sure you put the resigned song, which is now a custom by the game’s standards, in the 000001 folder.
You are about to leave Rhythm Gaming World and access the external songs DB. While no song or file sold for commercially available videogames is hosted there and only fan generated content is allowed, Rhythm Gaming World has no direct control over the database and no files are hosted here. Alright, we had to made you aware of this, now you can visit the database!