Don't know for sure but I think they should. I bought my DD some for her regular crocs and the back to the jibbitz is really pretty big. I think it should be big enough to fill the hole of the MM shape. Just be sure the jibbitz isn't a small figure. Hers is a pretty big butterfly.
Crocs are a type of shoe--very comfortable and popular for touring the parks. Jibitts are "jewelry" for the shoe. Crocs now makes a "Disney" Croc with the Mickey head.