Hi Brigabart,
As you know … researching all the controversial and conflicting information that is connected to safe, natural, ecofriendly, and organic (all of which are different) materials can be both frustrating and difficult because there is not enough information available to know all the things that people in your situation may really want or need to know with any absolute certainty (and there is a lot of misinformation you will encounter as well). Post #2 here though and the information it links to would be a good place to start.
Most people in your situation would be looking at natural fibers, latex, and innersprings in various combinations but since you appear to be sensitive to the smell of latex (even though it’s not toxic) then you would be limited to innersprings and natural fibers.
In terms of fire barriers … the two types that would likely be “safe enough” for you are either organic wool (that has no chemicals and is often used to pass the fire code in spite of what you may be reading) or an inherent viscose/silica fire barrier (some of these are Oeko-Tex certified and don’t use any harmful chemicals or produce VOC’s at any harmful levels again in spite of what you may be reading) and of course if a manufacturer you are dealing with offers it … no fire barrier at all is also a good option. Post #4 here along with post #2 here may also be helpful.
If you let me know your city or zip code then I’d be happy to point you in the direction of any local options I’m aware of that may be worth considering. There are many manufacturers that make an innerspring/wool mattress that would probably be suitable for wha you are looking for although they do tend to be more costly.
Phoenix