Snow White: 16th century (1500-1530) based on her dress. In Germany (based on the original fairytale).
Cinderella: In 1860, based on her dress, In France.
Aurora: 14th Century, based on the movie. Probably in Germany.
Ariel: 1836, based on that she met her autore in one episode in her series. She lives in Denkmark.
Belle: the middle of the 17th century,,when baroque architectural style was in mode, o in 1770 based on her dress. She lives in France.
Jasmine: in middle islamic time period, In Agrabah (based on her film).
Pocachondas: 1607, when the English settled in Jamestown Virginia to find gold. In Virginia, USA
Mulan: In the time of Hans Dynasty, Before Christ, based on the ancient Gods. In China.
Rapunzel: 1780 (based on wikipedia's information about Corona, Rapunzel's kingdom). In Corona, Germany (based on the movie).
Tiana: 1920 (based on wikipedia's information and from the movie of course). In Louisiana, USA.
Merida: In medieval Scotland, (I didn't found what time period)