The iCloud export only transfers the marks in the song, it does not transfer the song itself. Make sure that the song(s) you want to use are on your iPad and iPhone. If you are using iTunes Match (or iTunes in the Cloud) then you’ll also need to ensure that the song is downloaded first.
If you are getting the songs from Dropbox, then you will need to import the song from Dropbox on your iPad before attempting to restore the cloud configuration. I’m not sure why it wouldn’t appear on both your devices in Dropbox. Make sure you are logged in to the same account on both. If you have the Dropbox app on your iPad, see if you see the song there.