Teacher: I am a newly-escaped JW who spent 30 years supporting this organization as an elder and spokesman for the group. In that capacity, I was often asked to speak to school teachers and principals about how they could best work with JW children in their classrooms. I had a nice little dog and pony show, but the Q and A (questions and answers) part of the program was always challenging. Teachers had such amazing stories about the inconsistencies among JW children. Two dub kids in the same classroom would take opposite positions on whether they could participate in some class project. It was always difficult to explain that each child was influenced by parents, elders, congregations, all of whom had a different "take" on Watchtower rules.
This is very difficult to explain to reasonable people. The WT pays lip service to "conscience," often insisting that the organization does NOT tell people what to do or how to behave, but rather each individual has a "trained conscience" based on Bible teachings that determines what he/she will do in a given circumstance. Since individuals are at different points of spirituality along a pathway, they are bound to make different decisions given similar circumstances. At least, that's the way I was taught to explain it.
The truth is, the WTS does in fact have rules for behavior and expects compliance. When these rules impact the behavior and actions of Witness children, parents fall into two camps: On one side, parents will strictly impose and enforce behavors; other parents will "filter' these organizational requirements and attempt to protect their children by softening the rules. Thus, depending on the "parental units," you get different standards among children.
What's a teacher to do? Some excellent advice has already been given (above). Here's my two cents, based on experience with my own child(ren).
We had a teacher for one of our daughters who told us, "She knows what she can and can't do; I rely on her to tell me and I go along with her." In other words, the teacher communicated with the child and respected her wishes, regardless of what experience the teacher may have had with other JWs.
If you contact the Watchtower Bible and Tract Society, they may offer some additional advice. You will get more "real life, hands on" advice here, however; most of the upper echelon leaders of the WTS are childless. Anything you can do to lighten the load of these children, as many wonderful teachers have, will be a good thing.