Hi,
According to IRCC website:
So, if your card will expire in Dec, 2021, you should still wait. You should also
meet the residency obligations which can be found here:
https://www.canada.ca/en/immigration-refugees-citizenship/services/new-immigrants/pr-card/who-can-apply.html
The 9-month rule and RO requirements mentioned above also apply here. Whether you want to apply together or not is up to you. However, since your cards are going to expire in more than 9 months, you should wait. Whenever you all meet the requirements you can apply together. You can also apply separately whenever you meet the criteria. It's up to you.
Good Luck!