Undecided questions
(Spanish) Does this sentence make sense?

¿Dónde está él, mi amor? = Where is he, my love?
Note that in Spanish, if you want locate the vocative (in your example 'my love') in initial position, it must be out of the question marks: Mi amor, ¿dónde está él?

yes, you can. Ella is for girls and el is for boys.

¿Dónde está ella, (la qué es) mi amor?,
In the question mi amor = ella
Explnation ¿Where is she? + ¿where is my love? ¿Where is she. She, who is my love? That´s the sense.
Without poetry compisition, question is very simple ¿Where is she? ¿Dónde está ella? She is love of the person who made this question....Ella es el amor de la persona que pregunta. Saludos afectuosos desde la ruidosa Ciudad de México :))

In my opinion, the correct sentence will be "¿dónde está mi amor? Then if you (woman) say this sentence you're asking about a man. Therefore if I (I'm a man) say this sentence I'm asking about a woman. I think you have a literal translation english/spanish of a song. In spanish language we don't say "el/ella" it's understood as in prayer.