Given the 'pixel-size' of minecraft builds (blocks) are roughly half the height of the player, you would likely need to do an enlarged version (ie. features like doors are several times the two block size they 'should be') to get a good visual emulation of the movie castle.
Searching "elsa's ice castle minecraft" showed (in addition to a number of very impressive pictrures), a number of links to folks who've already attempted something similar to what you propose.
You didn't specify the platform or version of Minecraft you're playing on, but since you're in the Java section and assuming you're not averse to trying mods you could check out the Chisels n Bits mod (this gives you block sizes down to 1/512th scale or 64 units per meter-block dimension), the Forge Multipart mod, the ArchitectureCraft mod, or the Blockcraftery mod. These are all building-style (that don't touch any other part of the game) mods that can either improve your builds aesthetically or allow you to change the size scale.
Extremely heavy use of these pieces will eventually lag your game something fierce, but Chisels n Bits in particular seems to be highly-optimized with this in mind such that reasonably-large amounts have hardly any impact. Just keep in mind that, especially for Chisels n Bits you will need a crapton of time to get through all the creation tedium and you will want to develop a longterm storage solution centered around the bit bags.