Hi Supermariohhh,
You are certainly heading in a great direction and as you know I think highly of Cheryl (and Hans) and Cozy Pure.
Latex is certainly the most durable choice of all the foam materials and a suitable latex mattress that isn’t too soft should easily last you this long.
The Plus would be a logical place to start and beyond that your testing would be the most reliable way to find out which one is the most suitable choice in terms of PPP.
The odds are very high that one of their mattress designs would be a good match for you yes and like Hans I think that the Plus would be the best place to start your testing.
I still like my Lanoodles very much yes (you can see my comments about it here) and it would be a “safe” choice to add to any latex mattress to add some surface softness and “cush” with very little risk to alignment. I also sleep on a lanoodles pillow.
This would depend entirely if it was an noticeable improvement in terms of PPP. Your own testing is really the only way to answer this. If there is a noticeable improvement between this mattress and the Plus in terms of PPP then it would be “worth it” yes but what your body tells you is really the only way to know. I generally suggest that “just enough” pressure relief in your most pressure prone position is generally the least risky choice in terms of alignment but if you only sleep on your side and not your back at all (where thicker softer layers could be more risky) then it may be worth adding a little bit extra softness.
Phoenix