answer

1. when you are working in oversea, you still can apply your parents to migrate to oz, but u need to privide evidence that you have connection with oz, such as your partner and kid(s) are living in oz or have property in oz...
2. ur uncle can be a sponsor if his income is about 40K (need to check with centerlink)
3. Form40，Part E，Question15
if your uncle is a sponsor, this question relates to him, no you