Hi jner,
You have some great options to choose from 
The first thing I would suggest is to completely ignore any ILD information and focus instead on what your body is telling you in your local testing. ILD is only one part of how soft or firm a mattress will feel for you (and in many cases not even the most important part) and if you try to design your own mattress or use technical information to make comfort decisions then you risk being overwhelmed and any decision could take you many months or years of second guessing what your body is telling you. The “specs” that are important are the quality and value specs of a mattress but when you are testing locally then ILD information is not important at all.
What I would suggest is to first narrow down your choices to only one final choice at each retailer or manufacturer you are working with. Your feedback about mattresses you have tested along with their expertise and knowledge in more detailed conversations will help you do this. PPP (Pressure relief, Posture and alignment, and Personal preferences) is the most important part of local testing and “comfort specs” won’t tell you how a mattress will feel or perform for you. Quality specs which will tell you the relative durability and value of each mattress are of course important but comfort specs aren’t in local testing. I would also make sure that the mattresses you have listed from the online manufacturers are the ones they suggested in more detailed conversations and would be your final choice if you were buying from that manufacturer (not just put together based on theory or specs)
Next … when you are making “value comparisons” … it’s better to compare mattress only to mattress only so that your comparisons are more “apples to apples”. You can always compare foundations separately as well if you are buying one for your mattress. The foundation can skew any comparison between mattresses.
This is an example of how specs can be misleading. When you have very soft top layers (such as 14 ILD) … in some cases you will “go through” these much more easily and feel more of the firmer layers below them. There are many ways to make a mattress “feel” softer or firmer. This is why in some cases (depending on individual perceptions, body type, and sleeping style) … a thinner or softer top layer can actually make a mattress feel firmer. It also depends on which “type” of softness (see here) you are more sensitive to because softness and firmness can have different meanings.
I also tend to suggest that its a good idea to add about a 20% to 25% “premium” to an online purchase to get to what I would consider roughly equivalent online value vs a local purchase because of the lower risk that local testing and local service can involve. Once the local premium is more than about 20% - 25% or so (and of course the number would depend on each person’s risk tolerance) … then I would begin to look online more seriously.
Post #8 here along with post #46 here (about making meaningful comparisons) and your own “value equation” will be helpful in making final choices. Again … before any of this I would make sure you have had the more detailed conversations you will need with each manufacturer you are considering including all your input from your testing and their suggestions so that you are certain that the mattress you are listing is your final and best choice with that manufacturer (and you haven’t just used specs to put it together without a more in depth conversation with each of them).
I would also make sure that as much as possible your value comparisons are apples to apples (similar materials, components, covers etc) or at the very least do your best to identify and factor in any differences between them in terms of the value of any differences to you. For example the mattress you are looking at with Plushbeds is more comparable to The SleepEz 10000 Natural which can use the same two layers of 100% natural Dunlop but would have blended Talalay in the top so only one of the layers wouldn’t be directly comparable (100% natural vs blended). The one you were comparing has 2 layers that would be different (the two Dunlop layers) and the thickness of the top layer is different as well.
Once you have done all of this (especially the conversations) … it’s time to narrow your “final” list down to one. You may end up with several different types or designs of mattress at each one that either they have recommended or you have chosen … and this is fine. This where your own “personal value equation” along with your knowledge, intuition, “gut feel” and confidence with each of your final choices comes into play. There are many different types of layering which will work well for most people.
A few other minor comments which you may want to take into account.
The PLB is all blended Talalay
Jamestown 14 ILD is also blended Talalay.
Arizona Premium also offers a 3" top layer and this would make it more comparable in terms of layer thickness as well (and you would also need to choose either the blended Talalay or the upgrade to the natural Talalay at a higher cost)
I would also make sure you have factored in the ability to re-arrange layers or exchange layers or any other adjustments that are possible with each and the difficulty and cost of doing so as well as any other differences in what each manufacturer offers including any shipping or delivery costs and taxes.
Once you have eliminated your worst options (which you have) and are comparing “good to good” (which you are) … then my job is done and its time for me to step out of the way so that you can look at all the tradeoffs that are involved with each choice in terms of the mattress itself and the many other parts of “value” that come before, during, and after the purchase.
You have some great options to choose from and while I can’t help you with which one to choose, it would be difficult to make a 'mistake" in terms of quality and value with any of these. Hopefully though some of this can help you with how to choose between them based on all the objective, subjective, and intangible considerations that are most important to you.
Phoenix