Hi mdarnell27,
Only your own careful testing and personal preferences can answer questions about PPP (Posture and alignment, Pressure relief, and Personal preferences) because you are the only one that can feel what you feel on a mattress (see post #2 here).
I would need to know more about the specifics of each mattress you are considering (see this article) because durability will depend on the specifics of each mattress you are comparing but the post I linked in the previous reply has more information about the many variables that can affect the durability and useful life of a mattress relative to each person. In most cases it’s the top 3" to 6" of a mattress that will be the weakest link of a mattress … not the support layers or components … so while latex may be more durable than an innerspring “in theory” … in practical terms both can make very durable support components and it’s the layers above the innerspring or the latex support core that would generally be the weakest link in a mattress not the innerspring or the support core itself so I would make the choice between them a preference choice rather than a “better/worse” choice.
That depends on whether the latex is in a one sided mattress or a two sided mattress. If you buy a two sided mattress of any kind (with latex or otherwise) then it would be a good idea to flip and rotate it on a regular basis. If you buy a one sided mattress then all you can do is rotate it (see post #2 here). There is also more about the pros and cons of two sided mattresses in post #3 here.
There is more information in post #3 here that has more information about choosing a mattress for higher higher weight ranges but in general terms higher weights will tend to do better with firmer layers that those in lower weight ranges and I would be cautious with comfort layers that are too thick or soft because they will be less durable and could also be more risky in terms of alignment issues which can lead to lower back pain or discomfort.
This is another question that your own careful testing would tell you more than any suggestions I could make. While you probably don’t “need” more than 9" of latex … you may find you prefer it. There is more about thicker mattresses in post #14 here.
Talalay latex (and Dunlop for that matter) comes in a very wide range of firmness levels from ultra soft to extra firm so this would depend on the specific firmness of the Talalay layers (or any other type of material that comes in a range of firmness levels) and whether the design of the mattress was a good match for you in terms of PPP.
There is more about edge support for innersprings in post #2 here. Other than the edge support though, I would need to know the specifics of each mattress to make any more meaningful comments about them. One of the posts I linked earlier (post #13 here) has more about the most important parts of the “value” of a mattress purchase that can help you make more meaningful comparisons between mattresses.
Phoenix