clipped

With regard to the thickness of the concrete being 2" liable to break
from the movement and rusting of the rebar, how is this problem
avoided with concrete countertops, given that these are generally cast
pretty thin and poured in long sections with rebar and remesh from
what I have seen? Obviously countertops are subject to less tensile
pressure than something being stepped on, but are subject to
moisture.

Countertops would never be exposed to the amount of water that outdoor
applications are. Rusting rebar is a fairly common concern in Florida,
with all the balconies on condos....We have had a number of spots on our
condo where rebar had rusted and cracked concrete. This occurred on
balconies and second-floor deck in open atrium. Salt is an added issue
here, but concrete/stucco has to be painted and maintained to slow or
stop the problem. Condo across the street had 13 stories of balconies
jack-hammered, repaired and painted a couple of years ago.

I would also be concerned with the 8' length pavers cracking from
expansion and contraction. We have sidewalks with extremely long
sections and all the sections have cracked, roughly in the center.

With your clay soil and the possibility it can heave or shrink from
changes in water content, it seems that consistency would be the major
issue. If it rains, it will be evenly wet and expand fairly evenly, I
would think. Another reason smaller pavers would make a
difference...easier to pull up and re-level if the soil moves.