MAY DAYS: For certain members of the fashion flock, the next Memorial Day holiday will be remembered as a working weekend, albeit in an exotic locale: Louis Vuitton and its artistic director of women’s collections Nicolas Ghesquière have confirmed May 28 as the date for their cruise in Rio de Janeiro. The increasingly itinerant fashion season is to begin on May 3 with a Chanel show in Havana, Cuba, while Gucci is heading to London for its cruise showing on June 2.