Children’s Week runs from May 1st to May 8th this year. The WoWhead.com guide has been updated but we are not seeing anything new for this year.
You are allowed to do quests or achievements for the event unless they break the rules of whichever challenge you are doing (for instance questing will count for quests for Blood Thirsty challengers). Since someone will ask it, I’ll say it: Doing the quests or achievements that require you to bring the orphan into a dungeon or battleground will get you flagged.
You can earn toys, battle pets and pet care packages for pet related things… these are all okay to earn for your account, however, you would still not be allowed to use those pets to level up your challenge character.