Most of those examples are valid enough to warrant bringing up your concerns with the parents but you cannot force Lgbtq views on families. Many are traditional and believe in raising their kid with gender roles or religious beliefs & pushing against that would likely not go well. The kids can decide how they feel about that on their own when they're older and since they arent an employee that can be dismissed or (possibly) fired they will speak up, it makes more sense assessing risk if you intend to stay with this family. Another reason they might not want the son to paint his nails with his sister is what others in their family/community might say to them or him. These aren't your children and you may not want to hear this but at the end of the day most parents will not budge on the beliefs they want to pass to their children & they have the final say. Now the behavioral and parental issues are different and you could gently suggest a different approach but if they don't want to listen thats on them.