Celestephant is crocheted from the bottom up. She is crocheted in 2 colors. All parts are crocheted together except for the ears. These need to be sewn onto the head.
The dress is crocheted separately. In the pattern 3 colors are used, but it will look great in just 1 color too. Make the dress shorter if you like. The collar comes in 3 versions.

Using a different yarn and hook size will only affect the size of your Celestephant.