Hi kmanspace,
All the materials and components in a mattress (including the cover) will affect the feel and performance of all the other layers and the mattress “as a whole” so any differences in the covers or quilting materials along with any difference in the latex layers or the design of the mattress will have some effect on how the mattress feels and performs.
There will probably be “some” difference in the latex layers if the latex comes from different companies but if they are the same firmness then they will be “fairly” similar.
The cotton cover in the Arizona Premium mattress is a fabric not a batting material that is used for quilting (the wool is the quilting) and as you mentioned they have a stretch knit cotton cover and a cotton cover that is quilted with wool . There is more about the differences between a more stretchy knit cover and a wool quilted cover in post #6 here. While I don’t know the specifics of the cover in the Highlands mattress … based on their description it appears to be quilted with wool and latex. Both the mattress and the topper in the highlands are also two sided so both the mattress and the topper can be flipped.
In terms of the latex … the Arizona Premium upgrade to the 100% natural Talalay (from the blended Talalay) would be the closest “apples to apples” comparison in terms of the type and blend of the latex in the mattresses.
The Highlands also has a separate topper which will act and feel differently from the same layer inside the mattress itself. There is more about the effect of having a separate topper vs having the same layer inside the mattress cover in posts #3 and #4 here and in this topic.
The first “rule” of mattress shopping is to always remember that you are the only one that can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved that are unique to each person to use a formula or for anyone to be able to predict or make a specific suggestion or recommendation about which mattress or combination of materials and components or which type of mattress would be the best “match” for you in terms of “comfort” or PPP (Posture and alignment, Pressure relief, and Personal preferences) or how a mattress will “feel” to you or compare to another mattress based on specs (either yours or a mattress) or “theory at a distance” that can possibly be more accurate than your own careful testing (hopefully using the testing guidelines in step 4 of the tutorial) or if you can’t test a mattress in person then your own personal sleeping experience (see mattress firmness/comfort levels in post #2 here).
While your own careful testing or personal experience is the most reliable way to know whether any mattress is a good “match” for you in terms of comfort and PPP … when you can’t test a mattress in person then the most reliable source of guidance is always a more detailed phone conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart and who can help “talk you through” the specifics of their mattresses and the properties and “feel” of the materials they are using (fast or slow response, resilience, firmness etc) and the options they have available that may be the best “match” for you based on the information you provide them, any local testing you have done or mattresses you have slept on and liked or other mattresses you are considering that they are familiar with, and the “averages” of other customers that are similar to you. They will know more about “matching” their specific mattress designs and firmness levels to different body types, sleeping positions, and preferences (or to other mattresses that they are familiar with) than anyone else.
There is also more information about the 3 most important parts of the “value” of a mattress purchase in post #13 here which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability (how well you will sleep), durability (how long you will sleep well), and the overall value of a mattress compared to your other finalists based on suitability, durability, and all the other parts of your personal value equation that are most important to you (including the price of course and the options you have available after a purchase to fine tune the mattress or any exchange/return options that are available to you).
Phoenix