If we consider Amanita muscaria f. formosa (Pers.) Gonn. & Rabenh. as a color variant, then we should recognize A. muscaria f. muscaria also. This naming scheme is helpful for many reasons, especially for people trying to parse different types of fungi.
all var. have their own type. Only the autonym has the same type as the parent taxon. It is recommended to simply use the lowest valid rank for each type collection. However, Nathan prefers to keep the parent taxon as an active synonym because it is commonly used. Hope that is helpful.
You may wanna contact Nathan before you make sweeping changes. It would be a shame for you to have to “fix” everything twice.
they share the same type, they are different only in rank.