My speculation is based on the different cars we are seeing being tested on the "ring".
I believe we will have all models/trim levels available the first year.
I think the 6th gen will be stream lined and the ZL1, 1LE, Z28,SS, etc will be "trim levels" instead of separate cars, kinda like the 1L is with the SS on the 5th gen. So they will "share" drive line, but the "creature comforts" and styling will be adjusted by "trim level". I could be completely off, but it would help reduce the production costs