Giacomo is a common Italian name (James, Jacques in English) related to It. Jacopo and Hebrew Jacob. In Italy in honor of St. James, the apostle.
Yes, it is pronounced Ja' como.

http://italian.about.com/library/name/blname_giacomo.htm

As noted many times before, Kanaka is the Hawai'ian term for man; John Kanaka was commonly given to Hawai'ian crew members and harpooners on sailing ships, and to those who came to Canada in the service of Hudson's Bay Company, etc.

Neither name has anything to do with the New Orleans Marti Gras tune.