Under the terms as checked, each joining family member adds a processing fee and a gift, and derivatives at the immigrant stage must be a spouse or unmarried child under 21. Whether members can be added later is a question to put to the program in writing before deciding.
Cost per person and the daughter's age decide the sequence
Hypothetical example: her husband intends to keep working in Canada for two more years and their daughter is 18. Including the husband now adds a fee and a gift for someone who would not move immediately, and permanent residence for him would carry the same residence and tax expectations it carries for her. Excluding him may mean a later family petition once she is a resident, which for a spouse has its own processing time.
The daughter is a derivative now but the immigrant stage may take long enough that her age matters; the Child Status Protection Act can protect part of that time, but the calculation depends on timing the family does not control. Two written questions to the program settle a lot: can a spouse or child be added after the principal is vetted, and is any part of a family member's fee returned if that member fails vetting. Then a counsel's age calculation for the daughter.
Decide with those answers, not with assumptions.