I decided to list the big 2015 Fall releases.
October 2nd: Janet Jackson / Avicii
October 9th: Selena Gomez
October 16th: Demi Lovato / Pentatonix / Labrinth
October 23rd: Carrie Underwood / 5 Seconds Of Summer
October 30th:
November 6th: Little Mix
November 13th: Justin Bieber
November 20th & November 27th: 1 Direction, Rihanna, Kanye West (not confirmed yet but very likely)
It's unlikely that Coldplay will release the same day as these artists in my opinion except for Little Mix. So that leaves us October 30th and November 6th.
And if Adele is indeed releasing her album in November like Rolling Stones said, my guesses are November 6th and November 20th/27th (close to Black Friday)
October 30th is the only date untouched