In the 1980s, a Latin Spanish dub named "Los Pitufos y la Flauta Magica" is known to exist. The voice cast in the dub consist of the Spanish Smurfs TV cartoon voice actors. After the European Spanish dub's VHS releases were marketed in Spain, the dub is completely rare and hard to find.
In 2011, A user named UFL2001 finds a few excerpts of the Latin Spanish dub of The Smurfs and The Magic Flute and uploaded them to YouTube. However, there's still a complete version existing somewhere.
There is a link to Zima Entertainment's page about the film. Their DVD release contained the Latin Spanish dub. You can go check it out here: http://www.zimaent.com.mx/catalogo/zima-kids/la-flauta-de-los-pitufos/