I'm not sure who Stella Jang is specifically in this 'Love Story'. She could be an ordinary person sharing her own love experiences, or perhaps she's a semi - public figure within a certain community.
There are countless possibilities for Stella's story. It could be inspired by her dreams, where she envisions a world different from our own. For example, a world where animals can talk and they have their own society with rules and hierarchies. Or it could be a historical story, where Stella delves into the past and writes about an important event or a forgotten hero.
Stella might be portrayed as a kind - hearted and creative person. For example, she could be the one who always comes up with unique ideas to solve problems they face in the fanfic. IKKI Lemon could be confident and energetic, like someone who is always ready to take on new challenges and encourages Stella to step out of her comfort zone.
I'm not sure if there is an official fanfiction with such a plot. It could be possible that some fans have written it, but it might not be a common or mainstream storyline within the Lemonade Mouth fanfiction community.
Sadly, I can't tell you the author of the 'Stella Maris novel'. There are numerous novels with this name or something similar. You could try looking in book databases, asking in book clubs or literary forums. Maybe someone there has read the 'Stella Maris novel' and can tell you who the author is.
I'm not sure specifically as there could be many novels named Stella Maris. It might be about a character named Stella Maris. Maybe it's a story set in a particular location that Stella Maris is associated with, like a coastal town perhaps, and could involve her adventures, relationships, or some kind of personal growth journey.