Hi anatayw,
I think that one of the most effective ways to bypass “paralysis by analysis” is to put just as much importance on who you are dealing with as you do on which mattress you buy. When you are dealing with people that have the knowledge, experience, and integrity to help “educate” you instead of “sell” you … then you don’t need to learn what they already know and are willing to share. One of the most reliable signs of manufacturers like this are the ones that will disclose the details of every layer of their mattress. There is a great deal of information on this site that can be somewhat overwhelming but the best use of much of the information is to validate what a manufacturer or retailer is telling you to help you know which ones are the most knowledgeable and helpful.
This can make a very good choice for bed-sharing because latex is one of the “safest” materials along with natural fibers and innersprings. Even blended latex (which uses a blend of synthetic and natural latex) is a very “safe” material.
the subject of what is safe, natural, organic, and eco-friendly can be very complex and the edges between all these terms are often blurred even though they are all very different. Post #2 here has links to much more information about this that can help you unravel some of the conflicting and contradictory information you will be exposed with deeper research that can sometimes seem like you are going “down the rabbit hole”.
In general though … if you stick with more natural materials (natural fibers, natural latex, steel innersprings, fire barriers with no chemicals etc) then your odds are very good that you have a “safe” mattress that would be suitable for a baby, infant, or young child. If you decide to move into less natural materials … such as blended latex, or polyfoam, or some of the semi-synthetic fabrics like bamboo or viscose, then the degree of safety that you can find out will depend on the certifications that have been done on them (such as CertiPur or Oeko-Tex) and on how much you “trust” the testing protocols.
The only thing I would exclude completely from your choices for babies, infants, or young children is memory foam because of the potential risks that are involved in its use with very young children. Several of the better post and threads about mattresses and children are linked in post #2 here that may also be helpful. In the end each of us needs to decide “how safe is safe” for ourselves because there are often no absolute answers to these questions and each person will need to decide for themselves the “degree” of safety that they are comfortable with.
If you have questions along the way that i may be able to help with feel free to post them on the forum.
Phoenix