I think R8II will be same sensor as R6III with rest of the features mainly moved forward. I would assume that this will streamline sensor production and simplify the system.
I would love to see 24-70 2.8 and 24-105 f4 revised. I would prefer size and weight reduction over range extension.
The sensor in an R1 could be a staight upgrade in a C400/C80 replacement, or new models above those.
Dynamic range could be a stop better, readout is a bit faster, high ISO, AF are improved, too.
With proper cooling and a fast processor, it might be 6k120p capable.
There was a 5GHz WiFi camera certification that was classified until Mid-June which is the R6 V, the other certification was a 4Ghz which lines up with the R8 MKii retro camera.