If you are laid off, you'll need to find another "same or similar" job fast or USCIS may deny your I-485. Finding that next job will be more difficult if you only have an H-1B and not an EAD. So at a minimum, it is highly advisable for you to get an EAD for yourself. Kids don't need an EAD if they are too young to work, and your wife doesn't need it if she doesn't plan to work anytime soon.
If you filed your I-485 after last year's July fiasco and you paid the all-inclusive $1000+ fee for each person in your family, everybody's EAD and AP are included at no additional cost.