What the Girls did Wrong.

In no particular order:

Veronica adopts a duckling from the school science lab, which is probably petty theft. and she keeps the duckling on her person for most of the adventure, including the time she jumps off of a parade float rolling downhill. Veronica could have landed on the duck and broken every bone in its little body. Nobody who loves a small fragile animal takes it on a potentially dangerous quest. Veronica shows herself to be a bad pet owner.

For a prank during the slumber party the girls steal a large parade float from the marching band of a rival school. And that float should be large enough that stealing it is larceny. I think that as they left the float in a garage one of the girls asks whether they would return it. And no good person would agree to a plan to borrow someone's valuable property without permission unless the plan was explicitly to give it back soon. But one of the girls asks if they were going to return it.

So if the rival school or little sister Penny publicly reveals what they did, they could be arrested.

The marching band members of the rival school are depicted as rather sinister and intimidating, but they don't do anything wrong. They merely hold as hostage a small and comparatively cheap item until the the thieves return a comparatively large and expensive item.

When seeking information from Penny two older and bigger girls tie her up and begin destroying her toys and dolls to get her to talk. The movie gives no indication that they tried the tickle torture first before destroying another person's property. They could probably be charged with several crimes for that.

And when the girls wake up and find that Anna Maria is missing they agree to try to find her instead of telling adults and the authorities. If someone had broken in and kidnapped Anna Maria every minute's delay in alerting the authorities could lessen the chances of getting her back alive.

The girls do have quite an excuse for behaving like drunken and uninhibited adults. They were hypnotized by Mesmer to lose their inhibitions and then forget what they did at the party. So possibly Mesmer could get in legal trouble for not including a clause restricting what they would do to legal activities.

And maybe the girls owe it to Mesmer to to find him and tell him that they broke several laws and advise him to include a clause against crime in future hypnotisms.

It is claimed - possibly correctly - that nobody can be hypnotized to do something against their moral and ethical code. Mesmer didn't hypnotize them to do anything specific, but to lose their inhibitions and expand their horizons. I wonder if that means all of the girls have a high probability of committing more crimes in the future.