Concrete is one of the worst choices for counters, ever. It is just man made marble in behavior, without any of the pretty. It is porous and stain, etches, chips, and looks like your 30 years of stains garage floor very shortly.

https://www.houzz.com/discussions/2491784/the-truth-about-concrete-countertops

"Is it possible to install this particular sink in this particular cabinet, especially if I'm DIYing poured concrete countertops on top of the cabinets (not laying slabs)?"

Yes.

"And if so, how?"

Cast your concrete on waxed melamine and install the counters to the cabinets after they've cured.

Rip an inch or so off your cabinet side tops. Mount (2) Sink Straps to the cabinet sides; one set in front of the drain and one behind. Let the trimmed cabinet sides hold the sink in place while the top is installed. Silicone the sink flange, clamp the sink in place through the drain, check your reveals, tighten the straps, and remove the clamp.

Thanks for the advice and caution! We have concrete floors with "patina" and are leaning into the industrial look. I know it's not for everyone, and maybe I'll hate it, but I tend to think wear and tear can look cool. I don't necessarily want some shiny Disneyland-lookin concrete counter.

We are planning on pouring the concrete directly onto the cabinets using the Z Countertop forms from Concrete Countertop Solutions, so we will have to place the sink in the cabinet first, then cement board, then the concrete pour. I'm just unsure of how to secure the sink in place until the countertop is complete.

Also, why is it necessary to rip an inch off the cabinet side tops? Our sink manufacturer (Karran) suggested that resting it on the cabinet tops could actually provide additional support for the sink, in addition to the sink straps you suggested.

"Also, why is it necessary to rip an inch off the cabinet side tops?"

This allows you to mount the sink after the tops are in place. The 1" allows you to silicone the flange then mount the sink.

How else will you silicone the flange if you place wet concrete over it?

Ah, I see. So I guess I don't have to take an inch off the entire sides, just the part where the sink will go?

Also, do you have recommendations for where to buy these Sink Straps?

I guess Regent Stone Products doesn't exist anymore, and the GranQuartz site is giving me a forbidden error page.

https://www.houzz.com/discussions/2491784/the-truth-about-concrete-countertops IS the truth. They are terrible.