The date of Eradan's birth appears only in The History of Middle-earth volume 12, The Peoples of Middle-earth. It cannot therefore be considered completely reliable.
Eradan's name seems to contain the elements er-, 'one, single, lone' and adan 'Man', so the entire name can conceivably be interpreted as something like 'one man' or 'lone man'. If this is correct, it's unclear what significance this meaning might hold. Perhaps Eradan's name is an oblique reference to the fact that he was the first Ruling Steward to inherit the title from his father, or it may mean no more than that Eradan was an only child.