I am a schoolteacher and I have kept a corn in my classroom as a class pet. Right now I have a Leopard Gecko. Next year we will be breeding corns right in the classroom. It all depends on how supportive and educated your administration is on the subject. Your presentation was the victim of myth and misunderstanding on the part of the parents and other adults involved. What the teacher should have done was provided the parents with advance warning and a list and description of the harmless animals that would be there. Then they could chose to keep their kid out. The teacher should have arranged an alternative activity for the students whose parents did not want them to attend.
These are puppies; these things need to be well organized. Take from a teacher who runs a school reptile club and has a different snake in the class at least once a month.