As I stated elsewhere, after learning the hard way. Before I let a child pick up a collectible especially one I need, I do 2 things.

First I pause the game and check the path ahead to see if there are any yellow or red masks in the way. If there are red masks I hit them with lightening to get them to move. If yellow masks, I simply try to use another villager to move them out of the way.

Second, I carefully "lead" the child carrying the collectible by flying another villager ahead of him/her. By doing this, I can usually distract any aggressives who stumble into the child's path.

Caution: Do not use bees to clear the path. If you do, the child will drop the collectible as soon as they reach the bees.