Can I roast frozen squash the way I’d roast fresh cut-up squash? (For the Genius chickpea-squash-tahini salad)

Yes, you can roast frozen cubed winter squash (butternut or similar). I usually increase the oven temperature a little for frozen veggies, but keep a close eye on the time, since they'll cook at a different rate than room temp cubes would. Once they're soft in the middle and starting to brown on the outside, they're good.

Since the squash is being roasted with the chickpeas in this recipe, I might thaw the cubes before mixing with the other ingredients so your chickpeas don't end up too crispy. You could either thaw them in advance, or here I bet it would be fine if you spread the squash cubes on your sheet pan and popped them in the oven while it was pre-heating to defrost them a bit, then mixed them with the chickpeas and dressing before sticking everything back in the oven.

You could but it may not turn out crispy and robustly roasted as fresh squash would. Doesn't hurt to try if you're trying to cut down on prep time!