Hi SMCK,
I’m not sure where you are reading about all their specs because their description is missing most of the specs for the foam layers including the mygel memory foam, the 3" of “pressure relief” foam, and the base foam but they do mention that the middle layer is 3 lb memory foam which in combination with the other missing layer specs (which are also likely to be in a lower density range) would be enough to make me very cautious about this mattress and I would avoid it unless the only lower quality/density layer was the 1.5" of 3 lb memory foam.
I would be very cautious about using reviews as a meaningful source of information but you can read more detailed comments about this (which would also apply to any similar mattress) in post #2 here.
Yes … and you can read more about the specific in posts #2 and #6 here and the rest of the same topic.
This would depend entirely on the specifics of the mattress and the type and quality/density of the “foam” (latex and memory foam and polyfoam are all “foam”). Again … I would be very cautious about using mattress reviews (either positive or negative) as a particularly meaningful source of information and research (see post #13 here).
Their mattresses that are stocked and fulfilled by Amazon may be compressed and stored for longer than the mattresses they fulfill themselves but either way it’s not likely to be long enough to be an issue with the durability of the materials.
Phoenix