Getting rights for Weimar Republic songs

Dear Rich: I work at an educational, nonprofit and I am trying to clear rights for a few songs from the Weimar Era for an online, educational module to be used in classrooms. Now, the more I've looked into clearing audio permissions, the more confused I get.  It seems that I need to clear with the Master recording owner AND I need to clear for mechanical rights to reproduce the clips, as well as performance rights to transmit the clip.  Additionally, we'd like to include full lyrics in German and in English (translated). There are six different songs.  Four of them are from an album that was fairly recently recorded (which is making it easier to pin down permissions).  The other two are recordings that I don't have the original source for and the only information I have is the composer and lyricist. These are very old songs and some are fairly obscure (German Cabaret music from 1920-1930). We would like to do due diligence and attempt to find the correct entities and contact them for all the permissions we need, but does that mean contacting three different entities for three difference sets of permissions for each song? And then also reaching out to clear for lyrics? And who usually owns those? And what if I can't find the rights holders for a song through ASCAP, BMI, or general Googling?  At that point, can I put it to rest? Are older, non-American songs often held by organizations like ASCAP or BMI?  Does anything ever enter the public domain? Like I said, we are an educational nonprofit, and while I wouldn't think that we can get entirely covered via fair use, I'd hope that we could get something. Furthermore, I feel we need to prioritize the rights that are most important to clear.  Do you have any suggestions on how to proceed? Holy umlaut, that's one heckuva question (or like the Ramones said, "it's long way back to Germany.") We're not positive what you're doing with these songs (or what an online educational module is), but we're going to make an educated guess that it's all part of some schulkind's class work.  

The four songs on the album. As for the four songs on the album, the label that released the songs should be able to grant you performance rights (or lead you to the person who owns them) and the label should be able to lead you to the publisher (and the source for mechanical and lyric rights). So for those songs, you're probably covered.

The other two songs. As for the remaining songs, we'll assume that they were written prior to 1933 as that was the end of the Weimar Republic. We're not sure if you're talking about songs recorded back then or new recordings of old songs. If they're old recordings, it's possible they are in the public domain. In the European Union (EU), the copyright in sound recordings lasts for 50 years after the recording is published; or, if it's never published, 50 years after the recording
was made. Thus, all recordings made over 50 years ago are in the public domain
in these countries. However, this doesn't mean that the music that was recorded is
public domain. The copyright in a musical composition, as opposed to a recording,
lasts for 70 years after the composer's death in the EU. Thus, the
music on many old sound recordings is still under copyright in these countries, even though the recording itself is not. 

Sources for help. Have you tried GEMA, the German performing right society? They would probably be the best place to start research (and you'll probably need someone who sprechens Deutsche). Depending on your budget you can also enlist the aid of a music licensing specialist (easy to find with your trusty search engine). 

Bottom Line Dept. The Dear Rich Staff believes that if -- after all this research -- you cannot find the proper answers you can go ahead with your use. When its difficult to find authors or owners that's often because they're not to be found. In any case your diligent attempt to find the owner will go a long way towards muting any claims that may arise later. Chances are good that if you do eventually hear from the owners, they will only be entitled to a reasonable license fee. Also, if you really want to lower your liability for unlicensed material, figure a way to record the songs yourself. That way, the only possible liability would be limited to songwriter claims.