Hi there Heather!
Thanks for bringing your question to the Disney Parks Moms Panel. I love how excited your daughter is to see and meet Mulan. She is such a strong and courageous Disney Princess to admire. Although it has just concluded, the best way to see Mulan and Mushu is during
Disney California Adventure Park's Lunar New Year Celebration which will be returning in early 2019. Here you can see the special parade, Mulan's Lunar New Year Procession, which features these Characters as well as cultural dancers and music to celebrate the occasion. There are also special Lunar New Year Character meetings throughout the day near Paradise Garden Grill, and I have seen Mulan and Mushu take part in these as well. These greetings usual rotate between multiple Characters throughout the day, so be sure to ask a Cast Member in the area for more information on who will be meeting.
Another one of my favorite spots to see a tribute to Mulan and Mushu is actually hiding inside Disneyland Park's "it's a small world." When you are in the China scene, make sure to search for these Characters! I love finding the hidden Disney Characters throughout this attraction.
As always when you are in the park, make sure to also check the
Disneyland app under "Characters" just in case Mulan decides to make an unexpected appearance. I advise checking the app throughout the day for any changes or additions to Character greeting locations.
I hope this helps. Have a magical day!
-Jennifer