Requirements for Dependent Visa Application For My Child + Helper

I have a working(Z visa) and a working permit, and currently working on a 3-year contract. I would like to ask what is the procedure for applying for a dependent visa for my daughter. I want to bring her with me. Consequently, I would also like to know if it's possible to bring a helper from the Philippines who can look after my daughter. At this time, I am thinking of bringing my husband's sister. Will she qualify to be a dependent?

Do I need to have my employer issue an invitation letter for my dependents?

I haven't paid any income tax in the Philippines since I came to China as an OFW. Will I still be required to provide an ITR in relation to the dependent application?

Will I be required to issue bank statement?

Would appreciate any information that you can provide for me.
Thank you in advance.