This is one of those for which I just don't have the background.
Here in the United States, tomorrow, November 13, is the feast of St. Frances Xavier Cabrini, given at the rank of obligatory memorial.
In my Extraordinary Form Ordo cum missis propriis dioecesium Civitatum Foederatarum Americae Septentrionalis, (i.e. for the U.S.A.) which--quite sketchily and revealingly--does not list a publisher, Mother Cabrini is also listed for tomorrow as a iii class feast with the notation "US." However, in the back of the book, it is noted that in the dioceses of Indianaopolis, Joliet, Green Bay, Alexandria, and in the "vicariate" of Alaska, this is a first class feast not for tomorrow, but back on January 3.
Indeed, Mother Cabrini does appear on January 3 in my EF Missals, but only as a commemoration during the Mass of St. Gaspar del Bufalo, whom I am meeting for the first time in the course of this little investigation.
As if this weren't confusing enough, Wikipedia--from which I have lifted this lovely photo--lists Mother's feast day as December 22. Now as everybody knows, this is no time to schedule one's feast day, as you will be perpetually impeded by the proper Masses and Offices that ramp up to Christmas.
The date of December 22 (1917) seems to be her death date, which is a venerable means of establishing a feast day. November 13 (1938) seems to be the beatification date. I haven't figured out January 3.
Will the real feast of Mother Cabrini please stand up!
Even further, for Franciscans who might offer Mass in the EF tomorrow, it is also the iii class feast of St. Didacus. If it is indeed also the iii class feast of F.X. Cabrini, I wouldn't know who gets the day and who gets commemorated, given that there is no way (that I know of) to establish precedence, e.g. if one was a martyr, etc. Usually a missal would just let you know, but since these days are in different parts of the missal, Mother being in the appendix of American propers, and under a different day besides, it might get confusing.
Perhaps I should go consult with her in person. She's only a bus and two trains away. (Westchester #2 to from Park Ave. and Shonnard Place in Yonkers to 242nd and Broadway, 1 Train to 168th St., A train back to 190th St.)
In the end, as I have written before, if we are to fulfill Benedict's desire for a 'mutual enrichment' of the two forms of the Roman Rite, as he wrote in his cover letter to Summorum pontificum, these are exactly the sort of things that will need to be worked out in time.