"Edit Profile" page doesn't let you edit anything
Looking at the "Edit Profile" page:
. . . you notice there is nothing on this page you can actually edit. The fields' content is grayed out and you can not make changes, so the "Save" button is not appropriate here. I would recommend you remove it.
I assume that in order to change my Username or Email, I have to go to my FamilySearch.org Account and / or ChurchOfJesusChrist.org Account Settings to change them. I suggest adding something above or below these fields explaining where to make the desired change. I'm guessing that your FamilySearch account type (Member or Public) determines where you need to go to make changes, so this may require linking to the account type to determine which narrative to include. ???