Can I add a family member residing in a different country from mine?

No, all added members must reside in the same country as you.
This is a mandatory condition to be able to include them in your group on the Nusuk Hajj platform.
Yes, each added family member can log in to the platform with their own account, provided they use the same email that was used when they were added to the group. They will be able to view the information but will not be able to modify the choices made by the group administrator.