CCKg VS ESF

I'm still struggling whether my son should stay in ESF or accept the place in Christ Church Kindergarten. Can anybody give me some advice

I was told that graduates from Clear Water Bay School are promised a place in KGV if they start studying in P1 in Clear Water Bay. But for those who join the primary school in P2 or above, they can only go to South Island School. Is that true?

Among all ESF high schools, is KGV the best (with the highest academic standard)?

But CCKG is a Christian school (We're Christians). It develops students' interest in reading. Its school fee is lower (