I have read in some other threads that that's the way it's done, print, sign and scan for all the forms.
Imm008 you sign
Imm008dep your spouse sign
Imm5406 one for each member each one signs it's own form
Imm5669 your spouse sign
Important that whenever your spouse signs it's acting as the principal applicant for that form
One question though, how did you contacted irrcc for this process?, webform or they asked you to send a email to
CPC-CTD-Ottawa@cic.gc.ca?
I'm doing the same process but I have been waiting more than a month for their email requesting documents