The premix is palatable enough that many cats will lap it up as powder or mixed with water alone. Cats being cats, it is impossible to predict if yourcats will feel the same, of course. The ingredients in themselves are not something cats should have any objections to, like bone, egg yolk, and whey protein. Even the minor (in quantity) supplements we add, like A,B and E vitamins, Taurine as well as kelp, should not impact palatability negatively.
Much consideration went into the development of the palatability of the premix in addition to thedevelopment of its nutritional soundness and quality. The tasteless Xanthan Gum has been added particularly with clients like you in mind, to give the otherwise liquid supplement mix a creamy texture which evenly coats meat chunks and assures that the cats will consume a balanced portion and not only pick out the pieces of meat.
By pureeing raw liver to add to the premix, you can further disguise any taste of the premix your cats may object to. Your cats would perceive the meats chunks as being covered in a liver sauce. Prerequisite is, of course, that your cats like eating raw liver.