Zopiclone, zolpidem and zaleplon all bind selectively to the alpha-1 subtype of the GABA-a receptor, so yeah, the same binding site as benzodiazepines but more selective.
alpha-1 is associated with sedation and amnesia, while drugs selective for the alpha-2/3 subtypes are purely anxiolytic with little or no sedation. However as you note selective alpha-1 agonists seem to be anxiolytic as well.
Zopiclone and zolpidem both produce "psychedelic" effects, but personally I found zolpidem much milder, just some LSD-like patterning, fractals etc, while zopiclone actually produced hallucinations, seeing people that aren't there etc. Never tried zaleplon, be interesting to compare them.
The hallucinogenic effects seem to be GABA-a related as none of these drugs have any affinity for 5HT2A. Note that some other GABA-a agonists are also hallucinogenic, muscimol being the classic example but some people report psychedelic effects from some benzos like lorazepam and nimetazepam also.
No idea why some GABA-a agonists produce this effect while others don't, especially as many benzos actually markedly reduce the visual effects from 5HT2A agonists. If it was purely an alpha-1 subtype mediated effect you might expect that any benzo that produces strong amnesia should also produce visual effects, but nimetazepam doesn't produce much amnesia yet is one of the benzos most commonly associated with visual effects, and clonazepam which does produce amnesia, is one of the benzos that kill LSD visuals quite effectively, so there must be something else to it.