Always sounded like Lanois to me, but there are definitely a few people in there. Eno's billed as singing, but I don't know if he's on there...probably is. Adam & Larry may be in there, too...I dunno. But I think I can definitely pick out Lanois there.
As for it being played live....it was only 9 times:
· 1984-10-18 - Lyon, France - Espace Tony Garnier
· 1984-10-22 - Bordeaux, France - Pattinoire
· 1984-10-23 - Nantes, France - St. Herblain
· 1984-10-27 - Brussels, Belgium - Vorst National
· 1984-11-02 - London, England - Brixton Academy
· 1984-11-03 - London, England - Brixton Academy
· 1984-11-09 - Manchester, England - Apollo Theater
· 1985-02-02 - Munich, Germany - Rudi-Sedlmayer-Halle
· 1985-02-04 - Milan, Italy - Teatro Tenda Lampugnano
(courtesy of Axver!)
I think that youtube link shows a reason why it wasn't done more live. It's good, but it's nowhere near the power of the album version. They had a hard time with a lot of the UF stuff when playing it live. It's a shame there aren't more video boots of the UF tour...there are only a few out there.