Hope it's Kaaya, but I'd be surprised if they actually picked him as the starter. Expecting it to be Heaps.
The first thing the Heaps advocates mention to support their guy is experience. But his experience at two different programs was atrocious and he's coming off a season in which he finished 128th out of 130 qualified FBS quarterbacks in passing efficiency. Not to mention that DMoney has said Kaaya is the one who has displayed more poise under pressure this summer, which isn't surprising considering Heaps' propensity to completely fall apart in the face of a pass rush at BYU and Kansas.
Starting Heaps seems like a recipe for disaster whereas starting Kaaya would at least provide the potential to show visual reason for optimism for the future as opposed to more lip service. I would expect Williams to take over as the starter once he's ready if they go with Heaps, because I don't expect Heaps to perform well enough to hang onto the job based on his past experience.