Is it permissible to bring people and invite them to a school where polytheistic acts are practiced, even if the students are not forced to perform them? And does the ruling differ if those invited are children?

Islam encourages the practice of sports to achieve health and strength, but it may become forbidden if associated with prohibited acts. Bowing to anyone other than Allah is forbidden because it constitutes polytheism, as indicated in the hadith (definition) of Anas ibn Malik: "Do not bow to him." It is also impermissible to invite anyone to participate in a sport if you know that they will engage in something forbidden during it, because this constitutes cooperation in sin.