I hope this helps, this is the email I sent to all of my kids teachers. It was met with excitement and relief, and only one teacher who I am close to had any questions, which I gladly answered. I don't need to protect the Society anymore, and I shouldn't have to modify my answers to such questions. Below is the email.
Hello! Hope you weekend was a good one! This is ___________, my child(ren) in your classroom has/have some news they are excited to share with you, and have asked me to share it for them in email form. Recently our family has taken a different stance on our faith, which directly effects what we would allow or prefer as far as holiday celebrations and birthdays. As it stood BEFORE, we would have preferred our child not participate in any activities, but NOW we are open to whatever the child feels comfortable with. I know this change is big for them, and would really prefer that you let each and all activities that come into the classroom, holidays, birthdays etc, be an open option to participate if they feel comfortable, and if they aren't sure or don't want to, please understand this is different for them too. They may not know how to react, or how they feel about it. This is new and foreign territory for all of us, as both (Dad) and myself (Mom) were raised in the Jehovahs Witness religion, and have never celebrated any holiday or birthday. This is no longer our religion/faith as we have stepped away from it knowingly, and after much thoughtful consideration. It is no longer the faith which we wish to raise our children. So, if you will, please help navigate our child (ren) through what is exciting and new for them this year, we appreciate so much how you took our faith into consideration in the classroom, and hope that just as easily as you accomodated us in that avenue, that you can introduce the fun activities to our child (ren) in a way that is fun, acceptable, and totally THEIR CHOICE in participating, or sitting out the activity. If you have any questions, my email is always open to you, as well as a phone call. Thank you!