Hi kellyvotrenom.
Welcome to our Mattress Forum! 
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. There is more about the many variables that can affect the sleeping temperature of a mattress or sleeping system in post #2 here that can help with the choice of materials and components that are most likely to keep you in a comfortable temperature range.
You probably read this, but I’d keep in mind that it’s not really possible to quantify the sleeping temperature of a mattress/topper for any particular person with any real accuracy because there are so many variables involved including the type of mattress protector and the sheets and bedding that you use (which in many cases can have just as significant an effect on temperature as the type of foam in a mattress) and on where you are in the “oven to iceberg” range and also there is no standardized testing for temperature regulation with different combinations of materials …
As far as pressure relief on your current mattress, as you sleep prone/stomach but also on your back I’d keep in mind that combination sleeping is more difficult to deal with than someone who sleeps in one position since the different positions have different basic requirements. Since most of us fall in this group, it is important to choose a mattress (and in your case a topper that goes with your mattress) so that the combination is able to keep you in alignment as well as comfortable in all your sleeping positions. Fortunately, you’ve made the right choice purchasing something that is firm enough to keep you well aligned when sleeping prone. It is much easier to add a bit of plushness to solve comfort issues than it is to firm up a surface that is not supportive enough.
I agree with you that the best approach is experimenting and seeing what works for you.
As this is so subjective and depends on so many other interrelated variables it would be only you that will be able to determine if the combination of the temperature regulating qualities and the level of plushness and thickness that you’d need are what you need and prefer. Because of the uncertainty involved with purchasing a topper where you can’t test the combination in person … a good exchange/return policy can also reduce the risk of an online topper purchase so I would also make sure you are comfortable with the options you have available after a purchase to exchange or return the topper and any costs involved just in case a topper you choose also doesn’t turn out as well as you hoped for.
You are on the right track with considering latex, Talalay latex and Dunlop latex are extremely breathable materials, and they would tend to be good choices for someone who is temperature sensitive. Latex, in general, is also the most breathable and “temperature neutral” of all the different types of foam materials but the firmness of a mattress and how much you sink into it can also affect sleeping temperature as well.
Wool is among the best temperature regulating materials but I would also keep in mind that it regulates temperature in both directions (it’s used in the desert and also in cold climates because of this) so while it may not feel “cool” … it generally doesn’t feel “hot” either and it also helps to regulate moisture (which can trap heat) and reduce the perception of temperature that comes from higher humidity levels (similar to how temperatures feel cooler on less humid days than they do on more humid days). Wool may also reduce the amount of heat that reaches the memory foam so it can also firm up the memory foam or at least slow down the time it takes to become softer with body temperature.
As far as the two pads that you listed … bedding made from natural fibers or viscose materials (like bamboo) will also tend to be cooler than synthetic fibers but linen sheets along with silk are probably the coolest of all the natural fibers for those where sleeping temperature is a main priority. The filling in the first pad you listed is Revoloft Polyester Cluster/pellets Fiber Fill and I would be cautious about some heat trapping as well as the fact that both are relatively thin and may not be enough to accommodate your need for more plushness. On the bright side both of them have money back warranty and could be a good way to add more data points to your experiments.
Other than this … materials (mattress pads or protectors) that are “more” breathable and temperature regulating that what you have in any of your upper layers (particularly natural fibers or rayon/viscose types of fibers), changing your blankets or the bedding above you, or changing the temperature and/or humidity of the room.
There is more information about choosing a topper in [url= https://forum.mattressunderground.com/t/some-topper-help-appreciated]post #2 here[/url] and the topper guidelines it links to which along with a conversation with a reliable and knowledgeable supplier (that can provide you with good information about how their toppers compare to each other or to other toppers they are familiar with that are available on the market) can help you use your sleeping experience as a reference point and guideline to help you choose the type, thickness, and firmness for a topper that has the least possible risk and the best chance for success.
Hope this helps
Phoenix