It's an adorable pattern for a hoodie.
The other thing to consider is that the tension called for in the pattern is 14sts/4" (although the Thin Organic Cotton
knits ar 21sts/4")and the Drops Big Merino
is 17sts/4". Best thing to do is to try a swatch with your yarn and needles and see if you like the resulting knit fabric. You may not be able to get 14sts/4" with the Big Merino but perhaps you could knit a larger size and get that to work with your gauge.