You will need

Jacket
3 - 6 months (16in Chest) 2 Balls
6 - 9 months (18in Chest) 3 Balls
9 - 12 months (20in Chest) 3 Balls
12 - 18 months (22in Chest) 4 Balls
18 - 24 months (24in Chest) 4 Balls

Sweater
3 - 6 months (16in Chest) 2 Balls
6 - 9 months (18in Chest) 2 Balls
9 - 12 months (20in Chest) 3 Balls
12 - 18 months (22in Chest) 3 Balls
18 - 24 months (24in Chest) 4 Balls

Crossover Cardigan
3 - 6 months (16in Chest) 2 Balls
6 - 9 months (18in Chest) 2 Balls
9 - 12 months (20in Chest) 3 Balls
12 - 18 months (22in Chest) 4 Balls
18 - 24 months (24in Chest) 4 Balls

Hat
1 Ball for all sizes

7mm and 8mm Needles
3 Buttons for Jacket
2 Buttons for Sweater
2 Buttons for Crossover Cardigan