The morning mist is marginally more comfortable than the fiji but I am getting an adjustable base and based on some reading I have done I am concerned that the individualized pocket spring coils in the bottom layer of the morning mist will not bend properly with the base (we are getting the tempur pedic base–the one with the massage feature). We are going with two twins because my husband and I prefer different settings.
I know that this isn’t what you were asking but I would make sure that you know the quality of all the layers in this mattress before you purchase it so that you can confirm that there isn’t more than “about an inch or so” of lower quality materials in the upper layers of your mattress which could be a “weak link” in terms of durability (see this article and the guidelines here)
In almost all cases a pocket coil mattress will work well with an adjustable bed but I would always confirm this with a knowledgeable retailer or manufacturer because there could be a few exceptions as well and they will be the most reliable source of information about the specific mattresses they sell or manufacture.
There is more information about choosing an adjustable bed in post #3 here and the adjustable bed thread that it links to that may be well worth reading because there may be other adjustable beds that have all the features that are important to you that are in significantly lower price ranges than the Tempurpedic.