I prefer
Edith Isabel to your other suggestions. And I once knew the sister of an
Edith Linda Marie, which pretty well tells you her age, but it's still a pretty combo.
As for
Dottie ... no. Just no. And another no to
Edie.
Edith is short enough that it doesn't need a nn -
Edith Linda Marie was/is always
Edith, it seems.