I would be equally happy with either HLY or Norwegian.
As it is, we have just been offered a place at HLY and will most likely accept, since my son attends their Tots Club and is already familiar with the kindergarten environment and teachers. At nursery level (K1) it's loosely structured, meaning there's is free play, circle time, mandarin songs/words, and they are encouraged to do one piece of arts/crafts each day.
It's still comparatively a small school so there is still a friendly community feel about it. The only one hesitation I have, is that reception class (K2) is full day after autumn half term so I do feel that it's a bit long for a 4yr old.
On the other hand, Norwegian is half day for K1 & K2, but they also have a K3 year before primary level.
Also as I understand it, Norwegian will not start interviews for K1 until March so if you didn't get an offer it might be too late to find another place elsewhere, and I don't think I can put my HLY offer on hold for that long.
I didn't consider ICS since it's a bit further away, also it follows the US curriculum and we are British, and according to the SCMP Good Schools Guide it's "academically rigorous" whatever that means!
Anyway good luck.