Morph was referred to as "Sidney" and "Kevin" in Astonishing X-Men and the Blink limited series. It is unknown if one is supposed to be a last name, or a middle name with the last name not yet revealed.
All appearances in chronological order :
X-Man Annual ‘96
Tales of the Age of Apocalypse #1
Astonishing X-Men (1st series) #1-4
Amazing X-Men #4