Hi slumberseeker,
Welcome to the Mattress Forum! 
we have narrowed things down to a few that we feel we could live with and wondered if you had any thoughts. All 3 are CertiPUR- US.
The CertiPUR-US would refer to the polyfoams used within the mattress, and you’d want to make sure that all of the layers of polyfoams foams within the mattress are CertiPUR-US certified.
The materials you listed are higher quality and more durable, although you don’t list the thickness of the 2.5 lb polyfoam, and I’m wondering if there are other materials within the mattress. You’d want to be sure of the complete specifications before considering any purchase. This design is similar to the Therapedic MediCoil HD line or the old King Koil Extended Life Collection, which were better quality innerspring products.
You can read a little more about Paramount in post #2 here and the posts it links to. Unfortunately Paramount doesn’t normally disclose all the information you would need to know to make sure that there are no lower quality materials or weak links in their mattresses. The Paramount HD mattresses do tend to generally use some higher quality/density materials inside them (in a design similar to the Therapedic MediCoil HD line or the old King Koil Extended Life Collection) but the only way to know for sure whether a mattress has any weak links in terms of durability is to make sure you know the specifics of all the layers and components inside it (see this article). If a retailer or a manufacturer you are dealing with either isn’t willing or able to tell you all the information about any mattress you are considering, then I would avoid it because it would be a much too risky purchase.
This item would be the “odd man out” regarding configuration as compared to the other two. But without knowing the complete configuration and density of the polyfoam core as well as the makeup of the other layers on top of the latex (there are different models within this lineup), you’d have no way to make an informed decision.
As above, if you can’t find out the complete information about the componentry, this would be a risky purchase IMHO.
Phoenix