Yesterday, I sent author Robert Schoenberg the contents of the e-mail I received from author John Binder (see HERE) and quickly received a nice reply.
John's a very conscientious and reliable researcher, and my only (faint) hesitation in taking that birth date as gospel is the fact that it would have made K. [William "Klondike" O'Donnell] only five years older than Capone, and barely in his 30s when most of the action was going on; for instance, McSwiggin was killed in 1926, when K would have been only 32 if the birth date is correct. Yet the picture I got from the Sun-Times files shows a man who (at least to me) looks to be at least in his 40s. At this remove, I don't remember the details or where I got the information, but on p. 82 I wrote that he "was older than the general run of gangsters" and "much older" than Myles. OF course, can't say how much older.
The fact that your O'D was not nicknamed "Klondike" after all makes the coincidence much less startling, in fact barely a coincidence, neither "Wm." nor "O'D" being terribly rare.
SO I guess I have to backtrack and say the order of likelihood that they are the same person has become--in light of John's findings and the non-shared nickname--much diminished, maybe to the vanishing point.
Good luck with your book.
For now that pretty much concludes the current research into William O'Donnell. In the 25 years I have been dealing with history, authors, and historians, I know how "facts" can be mistaken by those who collect them. Therefore this is not a closed subject. I believe I have gone as far as I can for now. The information will be filed under Soap Gang member William O'Donnell for future research.
I want to publicly thank Marlene McCluskey of the Skagway Historical Society for making me aware of "Klondike" O'Donnell of Chicago gangster fame. I also wish to thank John Binder and Robert Schoenberg for taking the time to answer my questions thoroughly. Thanks to The Real Deal: Organized Crime Forum for allowing me to join their group and post my questions.