I doubt a Mini would have any M series processor. It would probably run too hot for minimal benefit. If the Mini 7 is not released until late 2024, I think it will come with an A17, or maybe even an A18 by then. I can’t see a 3 year wait for a new Mini that only goes from an A15 to an A16. Besides, a 3 nanometer processor would have efficiency benefits that would help with the smaller battery in an iPad Mini.