I do something really similar, with the exception of the chocolate variations, I just use semi sweet chips...but I use mini marshmallows instead of the fluff...much less mess!
I've also made the same recipe with white chocolate chips, and added food coloring and flavorings.... I've done a batch where 3/4 I left white and vanilla flavored and put orange food color and orange flavor in the other 1/4 of the batch...swirled them together to make a "creamsicle" fudge.... I've also used p'nut butter chips for p'nut butter fudge, and cherry chips, and then melted milk chocolate chips and mixed in chopped p'nuts and spread across the top....
I'm going to try yours tho, with the various chocolates!