Hi
At the Exarchate of Mexico Catherdral (OCA), the liturgical anthems that are sung are those of any OCA English-speaking parish (with melodies of Moscow tradition, not Ruthenian), translated to Spanish. The translations are in modern Spanish (they are not in archaic Spanish as in New Mexico).
The Antiochian Church now has a very good Byzantine-chant choir, and the liturgy is entirely in Byzantine chant, you can here some examples (I suppose they use the translations of Bishop Paul de Ballester but I'm not sure):
http://www.iglesiaortodoxa.org.mx/01-espaniol/07-publicaciones/01-grabaciones_galeria/paraclesis.htmThe Coptic Church in Mexico only uses anthems at the end of the liturgy while the whole liturgy is sung by the priest and deacon with responses sung by the faithful. At the end of the liturgy, a Spanish anthem commonly sung at Roman parishes is sung.
About three years ago I wrote an arrangement for choir of Palestrina and Victoria's "Trisagion" for liturgical Orthodox use (taken from their setting of the Improperia for Holy Week). I think it's been sung somewhere.
I also adapted for Spanish-speaking choir "As many have been baptized into Christ" from an Estonian traditional melody and two liturgical hymns by Peeter Laredei (Estonian composer) but I lost those files.