Look, EG7 instruction states that:
Additional family information (IMM 5406) form must be completed by:
You, as the principal applicant;
Your spouse or common-law partner
So it does mean that i have to send 2 application one filled by me as principal applicant and second one filled by my spouse as spouse or common law partner.
But this form doesn't have any option indicating to whom does it support (form SCHEDULE 1 also have to be completed by spouse, but this application have on the beginning the option indicating to whom this application belongs.
It seems very confusing.