I fear there is no real solution other than throwing away the work I've done with the horns and starting over. In some sense this may be a Kontakt issue I suppose. I'm very disappointed - I get such little time as it is to use this and I've been set back so far it's made it rather 'unfun'. I think it's a matter of somehow getting back to the version of Kontakt 5 I was using instead of the one that apparently comes with Mixcraft.
I typed 'all is not lost' when I meant 'all is NOW lost'.