One possible theme could be hope. Just like a star shining in the dark, it can symbolize hope in difficult situations.
Friendship could be a theme as well. The little star could make friends with other celestial bodies or characters in the story. It could show how friendship can develop in the most unexpected places, like in the vastness of space. And there could be a theme of growth. As the little star experiences different things, it could grow in terms of its understanding, power or simply in its personality.
Another theme might be uniqueness. If the little star is special in some way, it could represent how being different is a valuable thing. For example, if the little star has a different color or behavior compared to other stars. Also, the theme of discovery could be there. Maybe the story is about the discovery of the little star's hidden powers or abilities.
One possible theme could be friendship, as the little penguin might make friends with other animals in its habitat.
One possible theme could be love. Paris is known as the city of love. So it might be a story of a romantic encounter in Paris.
One possible theme could be exploration. The girls are exploring the world of star knowledge.
Perhaps family values could be a theme, as in many stories set in the Philippines, family plays an important role. Another possible theme could be the beauty of the Philippine landscape if the little star's story is somehow related to the environment there.
One possible theme could be protection. The people in the story might be protecting the little girl from various things like bullies or dangerous situations.
One possible theme could be the fear of the unknown. In many horror stories, the scariest part is not knowing what is out there. It could be that in your story, the main character is constantly in the dark about what is causing all the strange events.
One possible theme could be discovery. Margie might be discovering the beauty and uniqueness of Hawaii.
One possible theme could be growth. Just like many novels about young characters, the girl in 'My Little Girl Novel' is likely to experience growth both physically and mentally.
Friendship could be a major theme. My Little Pony has always emphasized the importance of friendship among the ponies, so in a true story, it could be about real - life friendships formed because of the franchise.
Independence could be another theme. She is away from home, learning to manage on her own in a new environment for a short time, like getting ready for bed without her parents' help.