They'll eventually want to bring it to the desktop line. I'm guessing when they refresh the units they'll release a touch bar keyboard for it. Battery might be doable with OLED too.
If there is a desktop version, I hope they keep the F line. There was plenty of room in the laptops for it to coexist with the touch-bar, there is no excuse to not have it on an external keyboard.
The Magic Keyboard has a more than decent battery life and a very small footprint. A slightly larger keyboard to accommodate the touchbar would have space for a larger battery and so I think it would work. Its the next logical step given Apple Pay on the desktop and the security benefits (plus others) of TouchID. One surely has to be in the pipeline.
If there is a desktop version, I hope they keep the F line. There was plenty of room in the laptops for it to coexist with the touch-bar, there is no excuse to not have it on an external keyboard.
Unlikely i think. They will want to promote the touch bar as much as possible, and there are millions of regular keyboards on the market one can buy if F-keys are needed.