shall have the same priority date as you and your hu*****and.
it will take around a year to get an visa interview. simple as long as you prove that you can afford your relatives's expenes.
I824 is generally filed along with I-485. after I-485 is granted, copy your LPR card (front and back) and send a letter to national visa center informing your status has changed. they should have approved your I-824 then and send the file to China for processing. you or your hu*****and will become the sponsor of your kidn. I-864 is a must.