It appears that the cubes are made of a light foam. Can you describe how “squishy” they are and how they interact with the foam of the floor? Do they slide, are they going to catch and cause the robot to drive over them?
I don’t know how to quantitatively answer some of your questions, so I will just do my best.
The cubes will compress & deform, but they are pretty firm. These are stiffer than say a soft sponge. As it says in the Field Documentation, they are similar in consistency to the foam field tiles.
The cubes have a very high coefficient of friction on the foam floor, however since they are so light (0.03 lbs - per the Field Specs) there is very little frictional force to oppose motion and they can be pushed easily across the floor by a robot. If you add some down-force, they are much harder to slide.
Thank you I think that pretty much answers my questions.