Right on with most everything, just a few comments:
I've been looking for a name for the combinations of different mutant alleles for a while and haven't found one yet. I would not call them "homozygous" as technically they are a heterozygous because the two copies of the gene don't match (the definition of heterozygous). It's just that most of what we call "hets" are one mutant with one normal and in this case it's one mutant with a different mutant of the same gene and no room for a normal copy.
So far I think the only mystic crosses with other members of this complex are mystic\\mojave = mystic potion and mystic\\mystic = super mystic. Both of those are dark snakes. If mystic = phantom which so far seems very likely then mystic\\lesser would be expected to be a BEL (karma) like phantom\\lesser. I've not heard of phantom\\mojave yet but that would be a good test of the mystic = phantom expectation.
I believe BHB or someone made what they thought was a lesser\\special and it was similar but some different than the mojave\\special = crystal. Don't know if there was any link to be sure it was the same special gene. The inheritance of crystal X normal (50/50 split of special and mojave and no crystals or normals) is another evidence that special is in the complex. The homozygous special has also been made and is a whitish snake that has a lot of yellow as I remember.