I would prefer
Mercedes Isabel, nn Cedie. A great Spanish combination.
Since
Mercedes is a Spanish name, I prefer the Spanish form
Isabel. And since
Sadie would be a nn for
MerCEDEs, I just like the spelling Cedie best.
"You sought a flower and found a fruit. You sought a spring and found a sea. You sought a woman and found a soul. You are disappointed."
"It does not become me to make myself smaller than I am." (
Edith Södergran 1891-1923)