Hi worldaven,
The options you linked in your last post would be more suitable and more durable IMO than the options you listed previously.
All of them include .75" of quilting polyfoam which by itself would be within the guidelines I would normally use (around an inch or so or less of unknown quality or lower quality materials). Quilting polyfoam also precompresses the foam which makes it firmer (tighter quilting patterns are firmer and looser quilting patterns are softer) and also increases the durability of the polyfoam.
The first two mattresses you listed (The Bowles HD Euro Style and the Bowles HD X Firm - double sided) use an offset coil that would generally be stronger and better quality than the continuous coil in the Lady Americana Bronze Sapphire - Semi Plush although none of them list the amount of steel in the innerspring which is the most meaningful way to compare different types of innersprings (and this information isn’t provided by manufacturers).
The Bowles HD Euro Style uses an additional inch of 1.5 lb polyfoam under the 2" of latex which increases the amount of lower density polyfoam to about 1.75" which isn’t bad but is also a little more than “around an inch or so” which I would tend to prefer. It is also under the 2" latex layer however so the latex would be absorbing much of the compression forces which would increase the durability of the foam below it so this would be an offsetting factor. They also don’t mention the type or blend of the latex but no matter what type it may be latex is a good quality material compared to other types of foam. Overall this would have minimal weak links because of the materials and the way it is constructed. You may or may not need a topper with this mattress depending on how well it matches your specific needs and preferences in terms of PPP but your own careful testing and/or sleeping experience would be the best way to know and if you did need a thin topper for additional softness and pressure relief it would probably be “close enough” that you could sleep on it for a while and use your actual sleeping experience as a guideline for the thickness and firmness of any topper that you needed.
The Bowles Bowles HD X Firm - double sided doesn’t have the additional inch of polyfoam so this wouldn’t have any weak links in the mattress. It’s also two sided which will increase the durability of any mattress and allows it to wear more evenly. The challenge with this mattress however is that it would almost certainly need a topper to be suitable for you (probably in the range of 2" - 3" or so) and as you mentioned this would increase the cost of your sleeping system. There is also some uncertainty in choosing a topper for a mattress that is the best “match” for your needs and preferences and you may not be able to sleep comfortably on a mattress this firm to use your sleeping experience as a guideline for choosing the topper. It would probably be the most durable of the three choices and you could flip both the mattress and the topper but it would probably be the most “risky” choice because you wouldn’t be able to test the mattress topper combination in person before buying the topper (unless Bowles sells a latex topper that you can test with the mattress).
The Lady Americana Bronze Sapphire - Semi Plush would probably be my least favorite choice of the three because of the lower quality innerspring and because it uses 2" of 1.8 lb convoluted polyfoam instead of the latex. 1.8 lb polyfoam is a good quality material and at the lower end of “good quality” polyfoam but convoluting polyfoam also makes it less durable than a solid layer because there is less material in the layer. Even good quality polyfoam is less durable than latex as well. They also don’t mention the density of the memory foam layer but it’s also very thin so this wouldn’t have a significant effect on durability. The biggest reason to choose this would be budget reasons rather than quality or performance reasons. It appears to be roughly the same firmness level as the Euro so if you could sleep on the Euro without a topper then this one would probably be fine as well. Overall I would say this one also has only minimal weak links in the mattress in terms of durability although I would rate it behind the Euro.
Part of your choice would be the risk involved in buying any topper you need because there is no guarantee that the first topper you choose will be the most suitable in terms of thickness or softness and choosing a topper always has some degree of uncertainty involved … particularly if you can’t sleep on the mattress first to help you make the most suitable choice based on the topper guidelines here.
All three of these are more suitable choices IMO than the ones you listed previously and the choice between them would be much more in line with choices between “good and good” instead of “questionable and questionable” and a final choice between them would be based on the criteria that were the most important parts of your personal value equation.
In terms of general design … the Euro has some similarities to the Telluride Plush at Denver Mattress (a mix of polyfoam and 2" of latex, over an innerspring) except the Telluride uses 1.8 lb polyfoam throughout and has no lower density polyfoam. The Telluride uses a pocket coil which is more conforming and has a higher coil count and has more foam over the coils so it wouldn’t have any obvious weak links in terms of durability but I would want to test it very carefully to make sure that it was suitable for you in terms of PPP because it may or may be on the soft side … especially for stomach sleeping. If a mattress is on the edge of being too soft for you then even a smaller degree of foam softening may put you over the edge in terms of PPP even though the mattress is still in relatively good condition.
Hope this helps 
Phoenix