I'll suggest to buy 2 sets of PE and 2 sets of formal day uniform.
Usually 2 days PE however, you may need 1 more day in case you will selected to some OLE which may need PE uniform.
For the formal day, you may choose 1 white, 1 blue Polo which give refreshment to your kid.
Definitely need the long sleeve jacket, sometimes aircon in school and school bus is cold.
Not necessary the orange and sleeveless vest. Only if you are invited to the school team for public performance then you will need the orange knitwear. This you can purchase anytime in the 2 Kingkow outlet.