Could the A6 be a Qualcomm partnership?
Since A5 and it's A9 cores are boring and A15 isn't ready, it would make at least a little bit of sense for Apple to partner up with Qualcomm. Krait is an A15-class core so that strikes out the boring part about A6 being simply an A5 die shrink.
The big advantage here is an on-die radio with LTE. However, you do get a slight downgrade in graphics and possibly major architectural changes there too.