I think beautifulday has had a gutful of Shenzhen life. We lived in Nanshan district, close to C Mall. Although that was an improvement over the rest of that shithole, we couldnt wait to get out of the place. Hated every second that we lived there, can stick that "cultural" experience where the sun dont shine.
Now, back to finding a positive sollution ..
Hong Kongs "Gold Coast" http://www.goldcoast.com.hk is the most location logical, especially now that the Lok Ma Chau Shenzhen route is active, you also have a very close mini bus commute to Shenzhen Bay from this part of HK.
Why on earth someone would nominate Kowloon Tong, obviously A/ doesnt have children, and B/ hasnt a clue, when the OP made it clear that they lived in paddington Queensland "Australia " previously. She'd rather drill a hole in her head than live in another built up crowded concrete jungle, after her SZ experience... Also, why on earth does it matter if she is close to any international schools, when she has an 11 month old child ? Hello ! I think we need cuban strength double shot espresso's this morning lol
Gold Coast has excellent pre school related facilities, where you'll find a mothers group, it also has a western supermarket and roughly about a 40% expat population, 20% mainland Chinese second home population ( not always here only for holidays ), and the balance is local HK people, which explains why its so quiet here ... I wasnt being sarcastic then, its true....
Gold Coast, Tuen Mun, Siu Lam, So Kwun Wat, are all handy to speedy access accross the border, and rents are going to be likely, 2 to 3 times what you would have paid for the same sized flat in Nanshan district SZ...
$7000HKD per month is going to be the min for a good sized 2 bedroom, and anywhere from that and $15,000 will get you something spacious, 3 bedrooms and a maids nook, with excellent club facilities, pools, a beach, marina, good restaurants, a pharmacy, western supermarket and enough outdoor el fresco cafe/eateries, to put a smile back on your face.
As to pollution, its not really any better here, than Shenzhen of late, it used to be better 3 years ago, but seems about as bad now.
Factoring all of your requirments, Gold Coast, not just their complex as GC is the name of a particular complex, but locals know the area if you mention it.
We live next door to the Gold Coast complex, and absolutely love our particular residential spot, it's the Stanley of the New Territories in my opinion .