A7 is already quad 4
A7 already has the power to drive the Ipad mini
https://www.macrumors.com/2013/09/27/a-closer-look-at-apples-a7-chip-from-the-iphone-5s/
I doesn't make sense to me that the mini will have an A7 processor. It will need to drive 4x the pixels which in my opinion means it will have either the A6X or A7X processor.
Though, I'm leaning towards the A6X because I feel that Apple will want to keep its costs down.
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The X processor has significantly greater graphics processing power. It's needed to run the extra pixels of the Retina display.
A7 already has the power to drive the Ipad mini
https://www.macrumors.com/2013/09/27/a-closer-look-at-apples-a7-chip-from-the-iphone-5s/