Hi bermannyc,
Assuming that you are referring to the Quilted Organic Cotton Deluxe Mattress … you can see my comments about it in my previous reply here.
If you are referring to the Latex sleep system here (I’m guessing without the topper which you wouldn’t need for a child) then there would certainly be no lower quality materials or weak links in this mattress although it’s significantly more costly than other similar mattresses that would be available to you.
I don’t know the density of the foam they are using so if you can find out and let me know then I can make some comments about the quality and durability of the polyfoam. Again though you probably wouldn’t need the topper for a child (unless you would prefer it for them to sleep on latex rather than polyfoam).
This mattress also uses high quality materials (6" of 100% natural Dunlop latex with a cotton cover quilted with wool) and it doesn’t have any lower quality materials or weak links either but is also in a higher budget range than other similar mattresses as well.
Overall I think that there are similar mattresses available to you in much lower budget ranges than any of the options you mentioned but outside of the White Lotus Foam with latex topper (which I can’t make any comments on without knowing the density of the foam) if all of these are in a medium firmness range or firmer then they would make a suitable choice for a child.
I would keep in mind that you really don’t need to test a mattress for a child because as long as you are comfortable with the type and quality of the material and it’s in a medium firmness range or firmer then it would make a suitable choice for a child regardless of how it may feel to you and there are certainly some similar mattresses that are available both locally or online in much lower budget ranges than any of these mattresses that would also be well worth considering.
Phoenix