One idea could be that the baby has a special power that tames the beast. For example, the baby's laughter might have a calming effect on the usually fierce beast.
Perhaps the baby is lost in the beast's territory. The beast, instead of harming the baby, becomes protective. This could lead to a heart - warming story of an unlikely friendship.
One idea could be exploring the Beast's past more deeply. Maybe a story about his life before the curse, his relationship with his family and how it all led to his current situation.
One idea could be that Belle discovers a hidden garden in the Beast's castle that has magical plants which can talk and offer her advice. Another could be a backstory for the Beast, like how he got cursed in a more detailed and different way than in the original story. For example, he was tricked by a jealous wizard who wanted the castle for himself.
One idea could be that baby Mario and baby Luigi get lost in a magical forest filled with strange creatures. They have to use their baby wits and little jumps to get through obstacles and find their way back home. Maybe they befriend a little fairy who guides them part of the way.
One idea could be that Baby Mario and Baby Peach go on a magical adventure through the Mushroom Kingdom, encountering new and strange creatures along the way. They might have to work together to solve puzzles to reach a special power - up that can save the kingdom from a new threat.
One idea could be a story where the baby in the 'baby project' has some sort of special power that the characters have to figure out how to manage. Maybe the baby can communicate telepathically and it leads to all sorts of comical and heartwarming situations as the characters try to understand what the baby wants.
One plot idea could be that Baby 5 and Sai are on a mission together. They start off not getting along well because of their different personalities. Baby 5 is impulsive and Sai is more reserved. But as the mission progresses, they begin to understand each other's strengths and develop a mutual respect. They end up saving each other during a dangerous encounter and form a strong friendship.
One idea could be about the baby's first adventure in a magical garden. Maybe the baby discovers a hidden path and meets talking animals who teach it about the magic of nature.
Perhaps a story where the baby malachite is a special kind of malachite that is prophesied to bring great change to its realm. Some might want to protect it while others might see it as a threat. The baby malachite then has to deal with all these different attitudes towards it. It could also be about its relationship with a wise old mentor who teaches it about its heritage and the responsibilities that come with its powers.
One idea could be a story where the baby Mikaelson has unique powers that start to manifest at a very young age. Maybe they can communicate with spirits, and this leads to all sorts of adventures as the family tries to protect the baby from those who might want to use their powers.
One idea could be a story where Baby Nightwing is discovered by the Justice League. They have to figure out how to take care of him while also protecting him from villains who might want to use him. Another could be a time - travel story where an older hero goes back in time and meets Baby Nightwing, and has to ensure his safety so that the future doesn't change.