Listen, sometimes a kid in a costume asking for candy is just a kid in a costume asking for candy.So give them toothpaste and brush and let them have their one night of community sanctioned candy solicitation.
Pagan religion predates Judaism, Christianity and JWism. Therefore, just about ANYTHING humans do could considered to be of pagan origin or association. Marriage and childbirth customs. Jewish feasts are based on seasons and harvests as much as any pagan (wicca/earth) type religion is. Times and seasons or family memorials like weddings, birthdays, etc figure into almost every human festival. Think about it. There is nothing a person can do, including wearing clothes and putting on shoes that I bet could not be related to pagan religion. So what do we do? Can we condemn every bit of humanity and its behavior? Or do we look at the reason a person is doing something? Are Susy and Johnny making their annual pilgrimage to worship the dead on halloween or are they looking to score a lot of chocolate bars (Dove and Hershey, preferably). Are you worshipping Saturnalia at Christmas? Do you know what Saturnalia is? (I used to be a JW and don't remember what the hell it is or if it was a person, a god or a planet they were worshipping!). Do you know or care who or what Eostre is? I wear a wedding ring and have no idea of its pagan origins.My reason, and yours, is not to worship the dead, honor Saturnalia, Eostre or a circle of gold. Gold stars could be said to have pagan associations-if you want to play that game-and I don't see anyone ripping up their kids perfect homework because their teacher stuck a pretty star on it. If one was to carry these things to their ridiculous extreme, they would need to go that far. Which brings us back to intent. What is your intent? And if my example is a ridiculous extreme, why isn't it ridiculous to tell a kid they can't dress up and charm their neighbors while collecting some candy when it is a custom that has no evil overtones unless you give it some?
Remember all the jokes that went over our heads as children? If we are innocent, then that is what happens-the 'real' meaning will go right over our heads. And if we have to be TOLD why something is pagan/wrong, it obviously is not our intent to be honoring pagan ideas with our activity. And whoever is telling you should MTOB. IMO.