We're eight days on from the Grand Final and two days on from the clubs announcement, I don't know why anyone would be expecting immediate confirmation of this stuff. Fixtures themselves won't be out until mid November at the earliest I'd expect.
I can't see them changing the top six format, and a top eight out of 14 would be silly anyway.
As for the Championship, thought it was confirmed that it's a 21-team comp back in August?
The RFL have confirmed that Championship and League 1 will merge in 2026 to make a 21-team league. Here's the pros and cons of that decision.
www.loverugbyleague.com