Short sleeved pullover and shorts in 3/6/12 and 18 months

3/3/4/4 skeins of the main color, sample shown in« Eco baby » from Debbie Bliss (125 m/50 g)
1 skein of the 2nd color
3.5 mm needles, 3.5 mm hook
2, 10mm buttons for the button band of the pullover
4, 6mm buttons for the shorts
Tension in St st: 22 sts x 30 rows = 10 x 10 cm (4” x 4”)
Cast on technique suggested: long tail cast on