Second Story: Elodie attends funeral of her brother's FIL wearing a white wedding dress and a tiara and laughing. She was kicked out for being disrespectful. She doesn't think she did anything wrong.
The common thread amongst all the antagonists - never underestimate how hard the ego of an insecure person will work to concoct a narrative where they are the flawless hero persecuted by wrongdoers on all sides
Elodie chose to go to the funeral. Therefore she incurs all costs related; flight, hotel, damaged dress. Kai would be better off just leaving his family and going home to his wife.
Short story after 4th talks about how the SIL steals from OP and gets caught. 5th full story is about a friend stealing OP's Fiancé and tries to take the reservation for the wedding
Third Story: Sandy still lives at home with her parents. She does not like working. She tells her sister she is marrying a CEO. She said she and her fiancé are a high class couple and her sister and her husband are a low class couple.