Perhaps it could center around a family that has been cursed. On Dia de las Muertas, the veil between the worlds is thinnest, and they have a chance to break the curse. They encounter various helpful and hindering spirits during their quest. The novel could explore themes of family, heritage, and the power of love and remembrance as they strive to end the curse.
A young artist. He could be using his art to connect with the spirits on Dia de las Muertas. His paintings might come to life, and he becomes involved in a magical adventure in the spirit realm to save his village from a dark force that is awakened during the celebration.
I don't think Darren Modok was featured in the comics. Usually, characters like this don't just pop up without notice or a lot of buzz among comic fans.
Darren Suggs' success story might involve his achievements in business, perhaps starting a successful company or making significant innovations in his field.