Hi lilly,
Post #2 here includes links to the better forum posts and topics about mattresses and children that should be helpful and also includes links to many good options and sources for children’s mattresses. It would be the first place I would start.
Neoprene is a form of synthetic rubber that is unusual to find in a mattress (I’ve never seen it used before) and it has a more closed cell structure and is less breathable than the more typical Dunlop or Talalay latex foam. I would find out if this is what they are using for sure since it seems “odd” to me. You can see here that the “typical” use of Neoprene doesn’t include mattresses.
When you are dealing with a child’s mattress then a firmer sleeping surface than would usually be comfortable for an adult with a more developed and “curvy” body would usually be the most suitable choice to help support their less developed body and keep them in good alignment. When they get older and need some additional softness on top of their mattress you can add a topper if the mattress you choose uses good quality and durable materials and is still in good condition. I agree with you that the benefits of zoning would be questionable for a child since it’s unlikely they would “fit” the zones.
Any good quality support system can work well for a children’s mattress (innersprings, latex, polyfoam) depending on your budget and the “feel” that you prefer (or think they would). Innersprings are of course more “bouncy” or “springy” followed by latex followed by polyfoam. If you spend time on their mattress with them “snuggling” or reading then how it feels for you may also be a worthwhile consideration. Many parents also feel better about innersprings or latex because they are a little more “natural” materials that have less likelihood of VOC’s but whatever materials you decide on I would make sure that it was “safe” and has been tested and certified for harmful substances and VOC’s.
Phoenix