Yes, you can transfer the overworld, eventhough you will have to redo the palette again. Just do this:
- Open the ROM with the OW you want to transfer
- Open the OW Editor
- Go back to Lunar Magic's Level Editor and open another ROM
- Go to the OW Edtior (you will see garble palettes)
- Hit save and you're done!
For music, it's not really possible.