You better wait on getting this bed as I just received a queen that compresses down to a depth of 2 inches. The product description is completely incorrect as it describes a 4 inch mattress topper. I bought a king of the exact same bed a year ago and it only compresses down to 9 inch depth and would support heavy people and we think it is fabulous. But the new one is being returned because it offers absolutely no support.

No

Zenus

I know for a fact that adjustable frames are sold with temperpedic and memory foam mattresses so it would arguably be yes.

Go to sleepys and look at a tempur pedic! it's exactly the same!

I think a block of firm foam, which is what keeps the mattress from sinking to the bottom. It did happen with a different one I had bought.

Yes, there are different firmnesses of a memory foam mattress. Generally rated by the weight of the memory foam (2.5lbs, 3lbs, 4lbs, or 5lbs).
This 12" in particular is a 5lb and tends to be more on the firm side. It is still quite comfortable but you will not sink into it as if you were ontop of a pile of cotton.
If you require extreme soft or plush then you may want to look for 3lb or maybe 4lb.

The reason I knew I wanted this mattres was my parent's, they had one when I grew up, it wasn't today's memory foam, but it was foam, or shall I say it is? Yes! it still exist!

From the research I did before I bought this mattress I found that it is a 5lb memory foam. Firm -- but not super firm. It does a pretty nice job especially when your body heat starts to warm it up.

They did have the queen size available but they may be out of stock. I wanted the queen as well and missed out because when i logged on to buy the queen options was gone. So we went witht he king and very happy we did. It is like having 2 seperate beds if you want to cause it is so big it is amazing! If u have the room go for the king.