Hi cstanger,
I think that both of these choices are good ones 
They each have different “benefits” and “risks” but this is part of the struggle of “final decisions” (which I know from experience can sometimes be harder to choose than the other 90% of the search). It’s great though when you really can’t go wrong and when you know that no matter what you choose you are getting better quality and value than the vast majority of mattress shoppers.
Wool is definitely a more breathable cooler sleeping surface and in the case of the SleepEz is used in a thinner more densified version as the fire retardant with their standard zip cover. The choice of whether to add it in the ticking quilting or to add it as a mattress pad on top or not at all is really about tradeoffs and what is important to each person. Post #2 here has some more information also includes some links (including a picture of the SleepEz unquilted cover) that should help in deciding which is best for you.
Phoenix