Live in DB/school HK island
I live in DB and prior to my daughter joining secondary school at Discovery College she attended an ESF school on the island. They need to catch the 7.15am ferry in order to meet the school bus. They are then on the 3.10 ferry home. There are a large number of children doing this journey and many mums have a rota to accompany them across in the morning and then meet them for the return journey. I'm sure you could arrange something with them. I could put you in touch with someone who does this with a number of mums. My daughter struggled with the early mornings initially (as did we!!) but once we were in the routine, my husband would accompany her on the ferry and got into work early. She enjoyed her Daddy time on the ferry.
Unless you pay the corporate debenture at DBIS there isnt a chance you will get your child into the school since I know how long the waiting list is. Also, DC is taking priority with people with HK permanent residency over anyone currently on their waiting list. My friend who has a child on both waiting lists at the same age as your child is leaving HK since she can't get him into school in DB and because of her other child, doesnt want to do the commute to the island. Sad situation.
Personally, I love living in DB, the friendliness of it and my two children have made a huge number of friends as well as friends for myself too. I previously lived on the island to experience HK life more but have to say I am happier living here but everyone is different and many of those who have never lived in DB usually give DB negative feedback. I have experienced it myself!
If you want any more information, I'd be happy to help so PM me. I work for a relocation/orientation company so if you need any guidance, let me know.