As long as the dependent is listed on the application for PR you will have to submit the clearance. Doesn't matter if they are accompanying you or will join you after you are done with your landing and stuff.
Well i am single applicant .i have specified my mom,dad and sis in family information.do i need mention all of them in dependants and submit pcc.mom and dad high rank officer back.sis working and married .
i think in ur case u may not require pcc for them...only incase u claiming points with their addition may require pcc logically...this is my thought lets wait n c wat seniors hav to say