I miss the days when there was actual competition with chipsets. Intel seems way too keen to put harsh restrictions on their chipsets for anything but their most overpriced chips, especially W.R.T. PCIe lanes and ECC support.
Sorry, not really, I've only heard rumours (from a reliable source though). It should be technically possible because coffee lake CPUs were demoed on previous chipsets. I doubt you are going to hear much from the motherboard manufacturers, they're probably more or less obliged to push the Z370. I understood the unofficial part as in not publicly available, at least not right away.
Disappointing that those boards won't see the new more cored processors.
There's some... interesting power consumption with the latest i9 OC'ed. https://www.eteknix.com/intel-core-i9-7980xe-extreme-edition...