Work Permit and visa for my Kids

I am a Swiss Citizen. I have an "Alien Employment Licence of the PRC" (Employment Licence). My kids will also join me. My question is: do I need to get my Employment Z first, and then get the family under the employent Z, OR do I need to send the kids passport together when I apply for my Z? What kind will the kids get? Also can you tell me how long it takes? Thank you vey much. Regards