As for the sibling issue, they're all HALF-SIBLINGS to one another. They all have the same dad, who is the emperor, but different mothers because the dad has been trying to get a daughter, who is the cure to the curse. He slept with different women in order to avoid falling in love with them because doing so would ultimately lead to his death. Had Chloe's mother lived, the emperor wouldn't have to keep trying for a girl and would happily fall in love with Chloe's mom because the curse was lifted when Chloe was found.
The eye color thing is also a bit off-putting and I find myself thinking about it a lot more than I probably should. BUT I forgive because the artist still made some attempt to color them, despite being quite lazy. I think it'd be nice to regularly have her eyes change color according to her emotions though :>