Those are column-stagger, aka columnar stagger or just columnar. That’s the ideal / ultimate goal in my opinion. Due to human fingers being different lenghts. But ortholinear still offers increased comfort / less strain than a standard keyboard. And it seems to be easier to achieve in the near term. Since it might be doable with just macropads and a custom cable to move the contacts of one of them.
Whereas column stagger would require either modifications to create more vertical space to fit off-the-shelf key switches, or waiting until Framework can perhaps bring us individual keyswitch units (intended for soldering into custom layouts). A lot more work and / or time.
For testing it out, some testing could be done with just 1 macropad and 1 spacer. This would be moving the macropad contacts to it’s the right side rather than left, and placing a spacer next to it. This creates an arrangement that, as far as the EC knows, should not be physically possible. And tests if it throws any issue for a custom arrangement like that.
Re the cost of 4 macropads, well, custom keyboards are expensive. People spend more than that on keyboards, sometimes a lot more.