Yes recorded Every Little Thing before Steve Howe joined the band, but he also did a Beatle coversong, it was with Tomorrow, Strawberry Feilds Forever - which I believe is the one of best if not the best Beatle cover-song.
YouTube - Strawberry Fields Forever (Tomorrow 1968)
The only song I know of Jon & Vangelis is the Friends of Mr. Cairo. And Vangelis also did the soundtrack to Chariots of Fire, probably one of the more recognizable sound tracks of any movie, because it is often used in comedy when someone is running in slow-motion.
YouTube - Vangelis - Chariots of Fire