If there's a mystery gene going on, and you include the bees, then the mystery would have to have come from the spider father. If you've ruled out the mother for sure.
For sure, you could rule out the pastel male and the cinny male as culprits because it looks like whatever is going on affected the bees as well as the funky pastel.
If mom was a virgin before this clutch....and the spider has sired multiple clutches without throwing anything unusual before this...then I would be pretty sure the mom is the one with something special going on.
I THINK...so long as you still have the mom...you still have a chance of finding something unique again, even if you sold the spider sire and the unusual pastel. Do you still have those clean bees? Might be cool to breed one of those back to mom in the future, if one is male.
(Sorry if you covered some of those answers about which snakes you still own in your original post...I'm having a hard time keeping up with my own history, much less anyone else's.)