There are a few characters in Fire Emblem: Seisen no Keifu with known full names, much like Elincia Ridell Crimea. These are Celice and Leaf: Their respective full names are Celice Baldos Chalphy and Leaf Faris Claus.
No information has ever been given on their fathers' full names, so Sigurd and Cuan's tags can stay as they are.
There are also a number of characters from Fire Emblem: Seima no Kouseki who use their English rather than their original Japanese names, such as Gerik's Japanese name being Xyst and the Selena from said game being known as Celina in Japanese. I recommend at least changing the latter name to the Japanese one, as there is already a Selena in Fire Emblem: Kakusei.
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