I can see them developing special chips for the iMac series, but not sure about laptops. The Macbook air im sure will just be a A14x with the pro's maybe getting a different one.
According to Gruman (Bloomberg) they're going to announce 13 inch Air, Pro and 16-inch Pro. I don't expect these would all have the same chip as the iPads. So we're likely to see some difference in the chips.
I'm guessing:
4 Big cores, 4 Little cores, for 13-inch Macbook Air
6-8 Big cores, 4 Little cores for 13-inch MBP
8-12 Big cores, 4 Little cores + dedicated GPU for 16-inch MBP
So probably 3 different chips, plus a dedicated GPU. So we may see 5 different major chips from Apple this year, although some may just be the same chips with some cores disabled, as it's common.