My guess is that the 4th gen Apple TV will be physically capable of streaming 4K content, but that it will not initially be supported due to lack of progress in contract negotiation with the content owners.
Certainly any new or revised iPhone will include both TouchID and an NFC chip for Apple Pay. The only data connection needed for Apple Pay is that via the NFC chip. Wifi/cellular is not required, so a revised iPod Touch could certainly be built by Apple to support Apple Pay.
I have not seen any rumors that Skylake-H (the specific Skylake parts suitable for a 15" MacBook Pro) will be released during 2015. I have no reason to believe that a Skylake MBP will be released before early-2016.
Absolutely not. That would have created confusion about which is the high-end machine: the 15" rMBP and the 17" cMBP as well as confusion about why there was no 17" rMBP. From a marketing perspective, that would have been disastrous. The recently introduced (or re-introduced) Retina MacBook is a perfect example.