Even if you didn't have much of a chance to get many of the Politi books, I highly recommend continuing into the Advent and Christmas season to try to locate some with the Christmas themed books and extend the study. Focusing on the traditions (Mexican & Mexican American) would be an enriching addition to the celebration of Christmas - Las Posadas, pinatas, tamales, nativity scenes.
Christmas Themed Books
Pedro, the Angel of Olvera Street (1946) - Christmas, las Posadas
The Noble Doll (illustrated 1961) - Mexico
Rosa (1963) - Christmas in Mexico
The Poinsettia (1967) - Christmas and Chanukah traditions
The Nicest Gift (1973) - Christmas
Lorenzo, the Naughty Parrot (illustrated 1992) - Christmas in Mexico