Did you make the song actually point to the copy of the UVB at the end of the song? It shouldn't be messed up if you did as you said. At least, I don't think it should.
To answer your question: There is no dependency outside of SMPS2ASM's smpsHeaderVoiceUVB. Switch that to a smpsHeaderVoice and you should be good to go. The only thing that differs a UVB song from a normal song is the goofy voice pointer. Once you put the UVB at the song's end and changed the pointer, you should be good to go, but it is awfully inefficient; it'd be worth trying to remove the unused voices. Look for the Voice Change commands (smpsSetvoice), and note the numbered IDs listed by them. Those are the IDs of the voices from the UVB that you want to keep. Once you have all the IDs noted, go through the UVB and copy the voices whose IDs matches those of the commands to the end of your song. After that, begin changing the Voice Change commands to match the new list of voices.
I want to say that backporting the Clone V2 to S1 is easy, but you've really got to know what you're doing. It requires a lot of code restoration, and even the relocating of the flag sound slots. Boo...
EDIT: Quoted due to page break