Monster School (partially found Japanese puppet TV series; 2003)
From The Lost Media Wiki
Monster School (バケルノ小学校ヒュードロ組; Bakeruno shōgakkō hyūdoro-gumi) is a japanese educational puppet show made by NHK, based on japanese folklore.
The series is about Nobiro, a normal boy, whose parents traveled to Africa to work, and he have to live with a family of Tengus. At school, he befriends other monsters of japanese folklore. The series focuses on teaching children the importance of communication.
No video from the series has been found online, although a video at Nico Nico Douga have the same name and description, it appears to be offline.
The show was aired in Brazil between 2003 and 2007, which can serve as a clue to episodes or scenes.