Hi Gynna.
I am glad that your husband still enjoys the ViSpring mattress and I agree that the shoulder pain when sleeping on your side could be connected with lack of pressure point relief which can be easily addressed by adding a topper to allow the shoulders to sink in more deeply and help to relieve pressure and maintain blood flow … this will usually solve a pressure issue. Of course you’d have to find the right balance of thickness/softness so as to not allow your hips/pelvis to sink in to deeply and put your lower back or pelvis out of alignment.
You did good research and based on your criteria all the combination of materials and the mattress types you listed would be good choices, provided that the firmness of the sleeping surface is in a suitable range for a growing child. They are all using “safte”, good, and durable materials (especially if you plan to use the same mattress for other children), Generally children tend to do better on firmer mattresses and for growing children that have transitioned to a larger mattress you’d want something more in the “medium” to “medium-firm” range, due to their epiphyseal plate and postural formation. Once you have decided on the types of mattress and materials you are comfortable with then you can read some of the general firmness guidelines in post #2 here for choosing a mattress for a child in different age ranges and Post #2 here that may also be helpful.
If you like the feel of an innerspring mattress, then you are correct that My Green Mattress Natural Escape would be a good choice. It uses 3" of Organic NR Dunlop (which is slighlly firmer than Talalay of the same ILD) on top of a 3 zoned pocketed coil spring system form L&P and would seem to fit most of your criteria (safe, natural, and breathable) The quilted wool cover would also give a little extra “cush” without affecting alignment and support. Girls usually tend to prefer softer surfaces than boys, but I’d still call MGM to verify that the 22-24 ILD range they list for this mattress would be suitable for your 3 years old daughter.
If you are looking at customization options for further changing the feel of the mattress when your daughter reaches teens then a component style system such as the one from SOL or Spindle would both allow for exchanging and rearranging the layers within. Generally, higher degrees of customization would become a more important consideration for older age individuals. You are comparing “good vs good” and I don’t think you could go wrong with either of them in terms of customization options, quality, durability, or value so any final choice between them would depend on the parts of your personal value equation that were most important to you and which one you were most attracted to for personal reasons.
There is no “best and worst” at this point … only what is best for YOU.
I’ll be interested in learning about your final decision and answer any other specific questions you might have.
Phoenix