Too much sand is a mistake. Sand is not stable, since the temporary wetting and compaction will disappear in the long run.
For paving stones (no dimension over 10"), the should be "set" in a screeded 1" maximum thickness of concrete sand on a compacted base. Follow up with a light fine (masonry) sand that is cast lightly over the surface and then a few passes with a vibratory plate compactor to draw sand into the tight joints and make the surface true. - Typical of real paver installations ranging from patios to streets and heavy duty installations of many acres.
For retaining wall block, they are normally set on a compacted base, but up to 1/4 inch of sand can be added if necessary.
Too much sand can be detrimental for strength and stability in both pavers and walls, especially when there are later rains and the pavers and walls can "swim" on/in the wet sand. - Typical internationally for pavers and retaining wall block.
How do pillars fit into the picture?
If you are using the larger "stepping stones", they are separated and allowed to move slightly with mother nature. If you are using common block dry stacked, you can expect them to move in the future.