Hi John,
Sorry I don't have any information on the people you have mentioned but I am sure that there is a connection somewhere as I would say all the Mizzi families from Gharb would be related somewhere along the line. If you are able to go back a little further I would probably be able to find the connection. If you are not sure how to research further back send me an email at c_frendo@hotmail.com and I will send you the details of where to get the info. Then I can help you after that.
The first Mizzi in Gozo was a Pietro Mizzi who emmigrated to Gozo during the repopulation after Turks took and enslaved population in 1551. Your wife would be a descendant of his.

Cheers,
Catherine