Here Come the Littles (1985)

Henry finds himself stuck with his cruel Uncle Augustus after his parents go missing in Africa. While enduring his uncle's greed and plans to demolish the family home for a shopping center, he discovers the delightful Littles, tiny elf-like beings living in the nooks of the house. With the help of Grandpa Little and his newfound friends, including a reformed cat, Henry uncovers Augustus's sinister intentions. Together, they gather proof of his wrongdoing, leading to Augustus's arrest and ensuring Henry's home remains safe, allowing for a joyful conclusion for all involved.