It says they claimed to he been a guitarist for six years in 1976, when they were 7. Not that they were 7 six years ago. What year do you think it is right now...?
The reason you can't find reference for Essaim is that it's actually spelled Etz Chaim (lit. Tree of Life), part of a Jewish prayer. Some anime using Judaism aesthetic for aesthetic transliterated it as Elohim Essaim way back in the day and that's just how Japan spells it now.