We have 2 dogs and we live in Happy Valley. There is a dog park up the hill and the neighborhood is full of dogs. If you havent visited the area, I would encourage you to take a look.
Commute to central will be small while commute to school will be manageable (approx 30 mins each way). As for schools, you will be very conveniently located for all Island schools and within easy reach of Kowloon Tong.
Chinese education is not for everyone, so I'll leave that one for you to decide.
If you have not yet contacted KCIS (English school) please check with them. They may still have some room for your 7 year old.
For the 2 younger ones, if you want to try the Cantonese, I would recommend LingNan kindergarten.
Feel free to PM me if you would like to talk in more detail.
HC