How can I roast hominy while minimizing the popping?
Well, since you asked for it, with a warning that I've neither cooked nor consumed roast hominy:

If you cover the pot with something that doesn't let steam out, it might slow or prevent the roasting. A stainless steel mesh would let the steam out while also keeping the kernels in. Alternatively, you could use some heavy-duty foil with a lot of small holes poked in it. You could probably also shake it instead of stirring, since the kernels will be contained.

As for preventing popping, I'd guess that dehydrating the kernels first would help. Certainly old, dried-out popcorn is known for failing to pop. And the physics make sense; its basically the water heats, creates intense pressure inside the pericarp, which then eventually ruptures, yielding a BLEV explosion. So if you have less water inside the pericarp, you'll have less exploding.

So I'd try dehydrating them before roasting. Maybe just leaving them out to air-dry (though that'd probably risk spoilage), or a very low oven. Or a food dehydrator.

I have no idea about slightly higher or lower temperatures. Possibly, lower temperatures would result in the water boiling slower, allowing it to leak it without exploding. Or maybe higher temperatures would have only a small portion of the water heated, and then it'd explode out, but only slightly rupturing the kernel (because it'd be a smaller explosion due to less water being involved).

Apparently weakening the hull actually improves popcorn yield, at least according to a patent Google turned up. But I'm not sure how you'd strengthen it instead.