I'm not sure specifically as I haven't read this light novel. But generally, 'koi' means love in Japanese. It might be about a love story that has something to do with twins ('futago'), like perhaps a love triangle involving twins that can't be separated ('warikirenai').
You can try looking for it in some well - known Japanese light novel online stores like BookWalker. They often have a wide range of light novels available, including many Japanese - origin ones.
Well, caricature carving knives often have blades that are specially designed for creating fine lines and intricate patterns. The handles are made to provide a secure grip. Some might even come in sets with different blade shapes for various carving needs.
Perhaps it's to highlight the importance of medical care or to introduce a heroic character who can save the baby. It could also be just a creative choice to make the cartoon more interesting and unique.
Overall, the 'Reiraku' anime is pretty close to the manga. There might be some changes for better animation or story flow, but they don't change the core.