ESF Cat 1 and Cat 2

There is this discussion in different threads about how ESF put students in Cat 1 and Cat 2, which causes confusion to parents.
Although my son studying in ESF Kinder was in the first-round ESF Primary interview and was subsequently given an offer, I have no idea if he is in fact in Cat 1 or Cat 2.
In my case, my son was born in HK. Both my son and I hold Canadian passports. I DON'T think that he is in Cat 2 as some other parents suggested. Based on all the facts recorded in the application form, he has the same