Dermosoft 1388 requires you to lower the pH. Since there is as good as no water present whilst your clay may have strong pH buffering capacity, doing so will be tricky. If you want to use levulinic and anisic acid, you shouldn’t add them in their water soluble salt form (i.e. Dermosoft 1388) but as free acids. Still, you’d need a low pH.
Heat treating your clay might also help.
The bacteriocins in leucidal (I don’t know which one but that doesn’t really matter) are likely to adhere to clay and the aspen bark extract is something which troubles me somewhat: Aspen contain an elevated level of salicylates but mostly as glucosides, not free and active salicylic acid. Unless Activemicrotechnologies hydrolyses that, their extract won’t be as good as pure salicylic acid. And BTW that one also requires a low pH in order to work properly.
Which organisms did grow in the challenge test?