There's a lot of fantasy in that article. The Clooneys dropped the Harkles right after Charles named one of the awards the Prince's Trust hands out after Amal.

Neither Jessica Mulroney nor anybody else was the Matron of Honor at the wedding. All the attendants were children. William was best man, sort of, but Charles and Doria did the honors signing the marriage license.

Most of the people mentioned are/were transactional friends who kissed the Harkles goodbye when they decided to cease being working royals.