Delmira was, originally, a nickname of Edelmira. And "pasión" is "passion", right.
Elba was, originally, a nickname of the names with the Germanic root alb-, "elf" (e. g. Alberica, Albrada, etc.). But it is used as independent name, influenced by the river name and the island name.
In Spanish, Elva can be: a) a name of Germanic origin in Spanish; b) a nickname of Elvira; c) a typo for Elba (V and B sound the same).
Justa is the feminine form of Justo (Spanish form of Justus). The sound of Justa is very different of the Gusta; then, they are two independent names.
Nélida is the adaptation of the French name Nélide (created by Daniel Stern), with the confluence of a nickname of Cornelia (Cornelia>Nelia>Nélida).
Perhaps Profe Esteban has a clue with Poro as nickname (from poroto?), but it doesn't come from the names.
Alira is an usual name in Argentina, but I don't know the origin neither the meaning. Perhaps a variant of Alirio (feminine name) "more feminine" for the ending in -A. Alirio is a name related with the flower name "lirio" (iris, lily).
Chuznelda seems a typo for Thusnelda, but I don't know.