Hi mikes425.
Nice to have you back our Mattress Forum! 
I changed your post back to an earlier thread you started in 2015 for continuing our discussion.
Heat issues can add up especially with softer pillowtop or thick memory foam upper layers because you will sink into the mattress more and the thicker layers of foam can be more insulating than a firmer mattress that you don’t sink into as deeply but there are also other reasons that some people may sleep hot on some mattresses.
In very general terms … the materials, layers, and components of a sleeping system that are closer to your skin will have a bigger effect on airflow, moisture transport, and temperature regulation than materials, layers, and components that are further away from your skin and softer mattresses or foam toppers will tend to be more “insulating” and for some people can sleep warmer than firmer versions of the same material.
I guess some of us are slower than others 
… it seems that you’ve “lived” with this frustration for quite a while now before making a new attempt to wrestle and solve it. Our discussion and input from 2015 still stands. I understand that a 14.5" mattress height + metal frame height is also an issue, but as I stated in my previous postings, before looking into the height issue I would make sure that the topper/mattress combination is suitable for your needs and preferences as I am always a bit cautious about adding a topper … unless you know for sure that you need a bit more plushness and also unless you changed your sleeping position from back to side in the last three years, you would probably still need something firm enough to keep you in correct alignment.
A topper can be a good solution for a mattress that is too firm and that just needs some additional softness and pressure relief (as long as it doesn’t have any soft spots or sagging in the sleeping surface) but I would be cautious about using a topper to try and “fix” temperature regulation issues because if a mattress is already a good match for you in terms of PPP then a topper can add too much additional softness and you could end up exchanging a temperature regulation issue for a back ache that is the result of sleeping on a mattress that is too soft. If some of the suggestions in the previous link (such as choosing a different mattress protector or different sheets etc) aren’t enough to solve any temperature regulation issues you are experiencing then I would consider a thinner mattress pad or topper made from natural fibers such as wool that can help maintain a more neutral sleeping temperature and have the least possible effect on the overall comfort and support of the mattress.
Generally, 2" of Talalay latex is more breathable than polyfoam and less “insulating” so over the course of the night it will sleep cooler than other types of foam materials. The overall sleeping temperature of a mattress also depends on the other layers and materials that are in the upper layers including the foam, or natural fibers in the comfort layers, the quilting in the mattress, the type of mattress cover material, the type of mattress protector used, any toppers used, the sheets, and the bedding, bedclothes which all have a combined effect on sleeping temperature and the ability to either store or disperse moisture and heat. There is more about tracking down a potential cause (or causes) and solutions for temperature regulation issues (at least to the degree possible for a specific mattress) in post #2 here and the posts it links to that may be helpful.
The mattress protector you have along with your sheets and other bedding and what you wear when you sleep will also have a significant effect on temperature regulation because they can either add to the insulating effect or to the ventilating and moisture wicking effect of your mattress. You can see more about the effect of different mattress protectors in post #89 here. Bedding made from natural fibers or viscose materials (like bamboo) will also tend to be cooler than synthetic fibers and linen sheets along with silk are probably the coolest of all the natural fibers for those where sleeping temperature is a main priority. There is more about sheets and bedding in post #7 here . In many cases changing the mattress protector, sheets, or bedding to cooler versions can make “enough” of a difference for many people who would otherwise sleep hot on a mattress.
All of this, of course, is separate from any environmental conditions in the bedroom (temperature and humidity levels with higher humidity adding to the perception of heat), on the physiology and tendency of the person themselves to sleep warmer or cooler and where they are in the “oven to iceberg” range, and on their weight and body type which will affect how deeply they sink into the foam layers of the mattress.
Lower humidity levels continuously allow more water vapor (and the heat it contains) to disperse into the air or be stored inside natural fibers (which in turn release them into the air more gradually) and away from the body so this type of cooling lasts throughout the night. This is the reason that wool is a great temperature regulator because it traps air which is an insulator when it is too cold but also allows humid air and moisture to be transported away from the body or stores moisture inside the fiber which keeps it away from the skin and keeps the cooling cycle going (which is why it is used in both cold and hot climates).
If temperature issues can be solved by adding a 2" Talalay topper and alignment and comfort checks out well then you are left only with the height issue and you could consider replacing your metal frame with a low profile 5" foundation (Charles P Rogers sells also a low “5” foundation that would work well with your mattress.) There is also more information about the types of support systems that are generally most suitable for different types of mattresses in post #1 here and it includes some links to some examples of each of them as well.
In other words … it’s always a combination of several interacting factors that determine the sleeping temperature of a mattress in combination with a specific person and environment and these issues are not easy to track down. You would need to think this through a bit as it relates to your specific circumstance.
Good luck with tracking it down and keep us posted on your progress
Phoenix