For Belle, as a barmaid, she could be developed as having a more street - smart side. She has to deal with all kinds of customers, so she becomes tougher and more resourceful. The Beast, in this AU, could start off as more withdrawn and bitter. His encounters with Belle at the tavern gradually soften him. He could learn about human kindness and humor from observing the interactions in the tavern.
If the grandfather is very warm and accepting, Shikaneji would feel relieved and happy. They might open up more about their relationship and their dreams. Nejire could start chatting excitedly about their future together, and Shinsou would relax and join in the conversation more. However, if the grandfather is not so friendly, they would be disappointed and perhaps a bit defensive.
Claire's reaction could be a mix of fear and determination. She would be afraid because she's in a vulnerable position, but she would also be determined to not let Ada succeed in whatever her plan is. She might start by trying to talk sense into Ada, appealing to her better nature if there is one. If that doesn't work, she would look for any weaknesses in Ada's plan or in their current location to make her escape and also try to find a way to stop Ada from doing this to others in the future.
A possible plot is that the tavern Belle works in is frequented by hunters who often talk about the Beast. Belle, being the curious and intelligent girl she is, starts to question their motives and the truth behind their tales. Meanwhile, the Beast, in his loneliness, sends his servants in disguise to the tavern to observe Belle. As the story progresses, Belle might get into trouble with the hunters when she defends the Beast, and the Beast has to come to her rescue, starting their relationship in a more action - packed way.
The Beast would likely be extremely worried and angry at himself. He might immediately rush to her side, blaming his own cursed existence for putting her in danger. His first instinct would be to protect her and find a way to ease her pain.
Another reaction could be that he tries to hide his feelings by putting on a brave face. He might joke around even more to cover up the fact that he's really hurt. But deep down, his feelings are still damaged and this could lead to some bottled - up emotions that might explode later.
It's possible that Ada and Claire are part of a fantasy world. Ada could be a shape - shifter or a magical being, and Claire could be a human who has stumbled into Ada's world. The licking of the neck could be a sign of recognition, like Ada is identifying Claire as someone special or as a potential threat in that world.
Ada and Helena are likely characters from a particular fictional universe, perhaps from a game or a book series that has a fan base creating fanfiction about them.
The Beast would be very confused at first. He has been the one with the beastly form for so long, and now seeing Belle in that state, he might feel a sense of guilt as if it was his fault. He would be protective of her, though, and try to help her adjust. Gaston, on the other hand, would probably see this as an opportunity to prove his 'heroism' by trying to 'save' Belle from her new form, but really he just wants to show off. Belle's father would be heartbroken and try to find a cure for his daughter, using his knowledge of inventions and books.