Hi rayz2k2,
On the description here it says they are using a 2 lb base layer. It would be a little more durable than 1.5 lb polyfoam but it would make more of a difference in higher weight ranges (once you start getting past around 200 lbs or so) than it would for those who are lighter because the base layers are usually a less important factor in the durability of a mattress unless you are heavy enough to “go through” the comfort layers and compress the base layers more.
They would be very different because the UD uses latex in the comfort layers which is very different from memory foam. There is more information about how latex and memory foam compare in terms of how they feel in post #2 here but they are about as different as two different types of foam can be.
They would be a much more reliable source of guidance about how their firmness scale may relate to the Tempurpedic mattresses but they would be so different that firmness comparisons between memory foam and latex can be misleading. Latex responds instantly to pressure but memory foam responds to pressure, temperature, and humidity and can start of firmer, become softer when it warms up, and be firmer again when you move into a new position so some people may call one firmer or softer and someone else may call the other one firmer or softer depending on their perceptions.
While the Dreamfoam mattresses are only available online … the list of better options and possibilities in the St Louis area are in post #6 here and I would encourage you to test some latex (Dunlop if possible since the mattress you are looking at uses Dunlop latex in the comfort layers) so you have a better sense of the general feel and response of Dunlop latex even if the mattress you test is a different firmness or design.
Yes … foam mattresses generally work very well on an adjustable bed.
No … you would need a roll pack machine to compress it again the way its shipped although it would bend around corners quite easily and you could probably fold it over and secure it with straps as you are suggesting (I would check with them just to confirm this).
While it’s certainly not necessary, there is a “sort of hidden” PayPal donation button under the “our services” menu item on the main menu bar and a small donation is certainly appreciated … and I appreciate your kind words as well 
Phoenix