Sorry, as a casual reader I rarely check references unless its really important to me at the time, and its been a while (at least five years) since I read up on this.

I do recall it was an annotation of the Enuma Elish that pointed out that although the fifty names were conferred by the Igigi, some were also the names of cities (eg. Nibiru, I think), and the listing was similar to the practice of Kings listing their military conquests. While the Igigi could have given up their attributes and divine portfolios voluntarily, it would be unique (Except in the case of Ea passing on his own name in addition to the fifty, thus bestowing absolute rulership to Marduk).

I've gone through what books I still have, but can't find anything on Daiwadana, so that part is entirely reliant on my memory.