In regards to Twilight: Breaking Dawn part 1 and 3, Coppla thought the story was too weird and decided to step away from the project after her first and only meeting. Here is the statement from the director about her experience from Rolling Stone:
“We had one meeting, and it never went anywhere. I thought the whole imprinting-werewolf thing was weird. The baby. Too weird! But part of the earlier ‘Twilight’ could be done in an interesting way. I thought it’d be fun to do a teen-vampire romance, but the last one gets really far out.”
Similar Topic: Actress Kirsten Dunst Helped Cast Cailee Spaeny For Sofia Coppola’s Book-based Film ‘Priscilla’
Bill Condon would end up taking up director duties for Breaking Dawn which was released in 2011 and 2012.
As for the live-action of "The Little Mermaid", this project was with Universal Pictures; It was a different take from the Disney version. But, things didn't pan out once studio executive asked her an odd question on how the film would appeal to older men. Here is a statement from Coppla about that experience:
“Yes, there was [a breaking point]. I was in a boardroom and some development guy said, ‘What’s gonna get the 35-year-old man in the audience?’ And I just didn’t know what to say. I just was not in my element. I feel like I was naive, and then I felt a lot like the character in the story, trying to do something out of my element, and it was a funny parallel of the story for me.”
Source: Yahoo