It's already been shown that GeekBar was looking at the wrong thing. So it's still possible that 2GB RAM is possible. In fact, for the 9.7" iPad, at least, 2GB seems assured.
Will Apple's SoC run at 2.6GHz? That's a good question. There are two types of CPU's. The first is what's called a narrow design, and runs at a high speed. Qualcomm's designs work that way, up to 2.7GHz.
The second is called a wide design, and runs on a much slower clock. The A7 is one of those designs. In fact, it's the only major SoC to work that way. Last year, it ran at 1.3GHz for the phone, and 1.4GHz for the ipad. Assumptions that it will run at 2GHz, or higher, are no more than guesses. If Apple were to double the running clock, they would need to make major design changes. Would they do that? Why? As all should know by now, it's not clock speed that tells us anything about performance when comparing two, or more, different processor families.
Last year, the clock speed was about the same as the year before, when they still had 32 processing, and a smaller manufacturing process. This year, the process will be smaller still. Apple can use that for more transistors to improve performance, or dramatically increase clock speed. Increasing clock speed by so much would, as mentioned, require major redesign. It would also limit performance increases in the future, as that's getting near the maximum clock speed. Better to increase clock by another small amount, and add to the core designs the way Apple has been doing all along.
So I doubt clocks will be over 2GHz this year.