We’ve been inundated with Apple headset rumors and speculation lately, but I don’t think I’ve heard any discussion of whether the headset will (or should) have its own cellular connection. As someone who always buys iPads with cellular, it seems to me that it should. However, it would add some marginal amount of weight, battery usage, and cost, all things that are rumored to be in short supply in this first generation design.
I haven’t heard any either. The pocket battery pack would be a good place for a cell radio. Though, the more complicated they make the battery pack, the more miniaturization and battery optimization needed to get rid of it.
AFAIK Apple’s 5G chips won’t be ready until 2024 and I doubt they would use Qualcomm for a new product currently targeted at developers. Anything is possible but this doesn’t strike me as a mobile device.