If you want to use the Edit button to change the "Allow Edits" property, that's fine but don't change the caption. As you can see, all rows change in sync because buttons are not bound. Access keeps only one isntance of properties for a subform so when you see multiple rows, all unbound objects will have the same value.
Don't worry that everything will be unlocked. You just need to lock the record in the Form's Current event. Remember - only ONE record is the current record. and only ONE record can be updated at one time so even though technically when you unlock the form , ALL records are unlocked, you can't have focus in multiple rows so in reality, only the current record is updateable.
To recap:
In the form's Current event:
Me.AllowEdits = False
In the click event of the Edit button:
Me.AllowEdits = True