Those popcorns are so much fun to make!
I used Bernat Baby Sport yarn and a size E/4 (3.3 mm) hook.
The sweater is made in one piece. Crocheting starts at the bottom of the front and ends at the bottom of the back.
The front has an opening with a small button.
And the blanket is very simple to make. It can be adjusted to other sizes (mine was about 38 by 27 inches).