Hi msuclay,
Just in case you haven’t read it yet … the best place to start your mattress research is the mattress shopping tutorial here which has all the basic information, steps, and guidelines that can help you make the best possible choices … and know how and why to avoid the worst ones (including the major brands). There is also more information that can help you compare latex to memory foam in post #2 here although in the end the the type of materials in a mattress you purchase is always a personal preference.
Not at all. All adjustable bases perform the same basic function and as long as you purchase a mattress that is flexible enough to be suitable for an adjustable base then buying the base first makes no difference.
I have also found Richmond Bedding to be knowledgeable and helpful about adjustable beds and they are one of the stores that I use for a “value reference” that are listed in post #6 here.
Buying an adjustable bed is more of a “commodity” purchase than a mattress because as long as the mattress you buy is suitable for an adjustable base then any adjustable base will work for that mattress. In general … I would choose an adjustable bed based on a comparison of the features or “bells and whistles” it has that may be important to you vs the price (see post #2 here in this topic).
Phoenix