My children attend ICS as mainstream students. We are expats from the US. There are some expats at ICS but there are more local families than not.
I am not sure why it is not popular with the expat community. I will tell you that it was our first choice since we chose to live in the NT to be near my husband's office. I know there is a huge wait list but typically, I think, most expats are granted admission as children transferring from a US curriculum are given priority.
Academically, the school is at the top of the charts in Hong Kong. Their standardized tests are the highest in HK as well as their AP scores from last year. I feel very confident that if and when we return to the US, my children will have a great advantage over their fellow classmates.
Regarding Bridges: while the children in the program (only 11 at this time) are in a contained classroom, they are mainstreamed/integrated with children of their peer group for certain lessons.
Parents of SEN children should inquire to the school for more information.