Does anyone have insight into any of the following questions?

1. Which Chinese Android App marketplaces are the most popular? In other words, if I wanted to target Chinese Android users, which app stores should I focus on submitting my app to?

2. Are there any barriers to submitting to such app stores for north american developers? Specifically related to getting paid.

3. Which Android mobile ad networks are best (cpm/cpc) for China?

Would love to hear any personal experiences working with China's Android Market!