I can't see your links dammit, I am making a Frozen one for this weekend too, and love the shards idea - I have never made them before so am off to google! Please link a photo when you are done - sounds like it will be great! I used to make all my cakes for kids from scratch but now I buy a good quality plain vanilla buttercake and use that for stability and then I make the buttercream to ice! I am doing a layered cake like a rainbow cake but all in ombre blue colours - hoping it will work!