It depends on the specific context and the author's intentions. Sometimes, it might be considered canon, but without more details, it's hard to say for sure.
I'm not entirely sure about the very specific 'real story' of Kars for Kids. But generally, it's an organization that is known for collecting car donations. It uses the funds from these donations for various children - related causes, like providing educational support or care for children in need.
The JJBA manga is indeed finished. It had a great journey and wrapped up with a satisfying conclusion for fans. However, there's always the possibility of spin-offs or related works in the future.
In the novel, Lil Shou was originally a human on Earth, but under some unexpected circumstances, he transmigrated to an interstellar world and became a member of a race called the Carl people. In this world, the people of Karl were usually described as cute creatures. In order to integrate into this world, they began to imitate the appearance and behavior of the people of Karl to adapt to this world. Sometimes, he would show the unique gentleness, kindness, and innocence of the people of Karl and establish a special relationship with them.
I'm not entirely sure as I haven't read it specifically. But generally, a light novel often has a unique story line, perhaps with complex characters and an interesting world - building. It might involve the adventures of the characters, their growth, and the challenges they face in the world of 'ultimate kars'.
One idea could be a crossover with the 'Jojo's Bizarre Adventure' universe where Kars interacts with other Stand users. Maybe he forms an unlikely alliance with a hero to defeat a common enemy.
I'm not familiar with the 'ultimate kars light novel' in detail. However, in most light novels, there are usually a protagonist and antagonist. So, Kars is likely the protagonist. As for the other main characters, there could be someone who opposes Kars, perhaps a rival with a different ideology or goal. There may also be characters that are important to Kars's development, such as a family member or a love interest.