Hello, 

I am a new baker, and recently made my niece a unicorn cake for her birthday. It was my second time making homemade BC. The crumb coat did fine. I put the cake in the freezer for an hour and when I began to frost it, it all went bad. The icing wouldn’t adhere evenly and even after piling more on, the scraper just kept pulling it off.

does anybody know it have any insight on what I could have done wrong? 

I am guessing, because the cake was in the freezer for an hour, it may have been condensating enough to prevent the frosting from sticking.  It is not necessary to put it in the freezer.  10 to 15 minutes in the refrigerator is sufficient for the crumb coat to crust and set.

It is a really cute cake, though, and the little birthday princess seems to approve, which is all that matters.

yeah what sandra said -- a crumb coat can go in the fridge or air dry for a little bit, either way  -- your little niecelette is aDORable -- you made her day!

There is NO REASON to fz a cake just to 'set/dry' the crumbcoat.  I don't know where that idea sprang from - it is totally UNnecessary.  It should take no more than 5 to 10 minutes  at room temp for a crumb coat to set up .(well maybe if the roomis HOT up to 15).    When I did 3, 4 or more tiered wedding cakes by the time I crumbed all the tiers the 1st one I did was ready for the finish  icing.

And ditto what K8 said, you nice sure looks happy! :) 

Your cake is precious!  Your icing may have been too stiff.  Adding a small amount of liquid at a time until you have a creamy texture makes frosting much easier.  The more you do it, you'll find the texture that works best for you.  Just takes time and practice.  If you get it too soft, you can stiffen it back up by adding conf. sugar.