It would be very hard to accomplish that with the current lineup of Intel parts and realize decent performance. If the release is truly soon it is either an ARM part or an unannounced 14nm part from Intel. The really out there possibility is an AMD part made by TSMC on their sub 20 nm process.
The current A7 isn't good enough. Of course that says nothing about A8. The problem with A7 isn't just the CPU either, the GPU really isn't up to laptop duty. If they did go ARM it would be a new processor tailored for higher power operation but most likely under ten watts.
Don't forget Apple needs to support TB in the AIRs. ARM would mean that Apple has the potential to build their own TB hardware.
I often wish intel had assigned the codename skylark rather than skylake. It's mainly because I think larks are interesting looking birds. Intel has been increasing integration. I wouldn't necessarily call it evolutionary in spite of their having absorbed components for years. They have been more aggressive in recent cycles. I'm just really skeptical about such a large jump in spite of Apple's willingness to embrace some minor to moderate specification downgrades or sidegrades to bring something new to market.
Could be. The Haswell-Y series performs ok at the maximum TDP, it's around a 2010 dual-core i5:
The fanless designs might be restricting it below the maximum power but a small fan could be enough to keep it higher power:
I remember you being one of the few people on here to advocate fanless designs. I mention that as an accreditation. I still think it's early though. These rumor mongers like to latch onto whatever they feel may becoming next, regardless of whether the timing is likely.