Homemade apple juice sweetened flapjack to set the right tone should?
seriously there is no lunch box police,
DD's friends have had skittles, all kinds of sweeties, crisps, chewing gum etc.
I always went for oat based things as only one of mine wouldn't moan bitterly without a substantial snack.
As for the mask on day 1 of p1 @detrimentofchildren I'd use my judgment, if you slipped it under your chin at a critical goodbye moment in the outdoor playgroup the worst that'll happen is that you'll get a snooty ParentMail reminding you of the rules but as new parents won't be on the system yet you may not even get it!
I'm sure most reasonable parents would understand and any that didn't would be an early warning indicator of who to avoid.