If I'm reading your post correctly, you have entries in your Family & Friends list for your wife and daughter that you manage BUT they have their own MDE accounts which you want to connect to?
If so, select "Update" for their profiles in your Family & Friends list and then select "Share Planning with {name}". This will allow you to enter the email address they used when they created their own MDE account. Both your wife and daughter will need to log on to their MDE accounts and approve the friend request.