Hi Migela,
Most (although not all) people that are looking for an “organic” mattress are usually concerned more with “safety”. There is more information in post #2 here and the more detailed posts and information it links to about safe, natural, organic, “chemical free”, and “green” mattresses and mattress materials that can help you sort through some of the marketing information and terminology that you will encounter in the industry and can help you differentiate between them and answer “how safe is safe enough for me” or “how organic is organic enough for me” so you can decide on the types of materials you are most comfortable having in your mattress. These types of issues are complex and are generally specific to each person and their individual sensitivities, circumstances, criteria, beliefs, and lifestyle choices.
There is also more information about the different levels of organic certifications in post #2 here and some of the benefits of an organic certification in post #3 here and there is more about the different types of organic and safety certifications in post #2 here and more about some of the differences between organic and safety certifications in post #2 here that can help you decide whether an organic certification is important to you or whether a “safety” certification is enough.
Post #4 here includes several links to lists of the better options or possibilities I’m aware of that are in reasonable driving distance of Wasau, WI but the only one that is local that I’m aware of that would carry any latex mattresses would be Verlo,
Latex is “good” for motion isolation/motion transfer but it’s not as good as memory foam which is “excellent” (see post #18 here). There is also more about motion isolation and latex in post #4 here and in post #2 here and there is more about the pros and cons of latex vs memory foam in post #2 here.
The thickness wouldn’t make as much difference as the specific type and firmness of the latex in the mattress, the type of cover and quilting material, and the overall design of the mattress.
Different people can be much more or less sensitive to the different types of motion transfer so the best way to know whether any specific latex mattress is “motion isolating” enough for you will be based on your own testing (with both of you on the mattress) or your own personal experience.
Phoenix