When applying, I wouldn't mention the temporary conditions. Many schools would turn you away just because they could open the place for children who will be here for a while.
It's not a bad time to move to HK though, rumor has that there will be many families moving after Chinese New Year (or this summer) due to the financial crisis--it may make it easier to get into the school you'd like.
HKIS is probably the most "American" school in HK because they place students from the US in their first round of applications. Hong Kong Academy may also be another option for you. From what I understand about the American School (I'm sure someone will correct me if I'm wrong!), their population is not primarily American children. According to the statistics on their website, 76% of their student population does not consider English their first language. Not really a problem if you want an international experience, but if you want a seamless transition, it's probably not going to be the place for your daughter.
Another option is to homeschool and then have afternoon activities. There are so many options here for drama, dance, sports, art, Mandarin, etc. Look into the laws re: homeschooling here though. If I understand correctly, you may need to work with an accredited/registered school.
Feel free to PM if you have other questions. I feel like I've just waded through the school maze myself!