Yes, 20K will start launching in September

This is the Fall/Winter Act 2 collection. Chanel alternates their bag releases and most models (except for the 19 due to its current hype) get released every 2nd collection. E.g. Coco Handles come for Métiers (20A), Fall Act 2 (20K) but not Fall/Winter Act 1 which is in between (20B). After that Coco Handles will come for Spring/Summer Act 1 (21P launching in January, not for Cruise 21C launching in November) and then again for 21A, not for 21S.
So basically Coco Handle come for:
20A Métiers - July 2020
20K Act 2 F/W - September 2020
21P Act 1 S/S - January 2021
21A Métiers - July (?) 2021
Same goes for classic flaps and Reissues which also alternate seasons. 20B will focus on Classic Flaps and Gabrielles as well as Business Affinity.
I unfortunately cannot tell you which colours will come. Not sure anything has been posted anywhere at this point as production is behind. There were some pictures floating around from the show, but not sure in which thread they have been posted (think there is a 20K thread already?).