UnScramble this Word: l j a n c i g o?

Questions

Name the artist of this song made with invented words "Solar prestige a gammon" (1974)?

25 March 1947?

What is Elton John's first band , before he started the solo career?

Which singer took his stage name from these two persons' name, "Long John Baldry" and "Elton Dean"?

Which is Elton John's first album?