After searching a bit for more Langrisser cds..
Found what is probably the last album we do not have:
There's a 8cm Drama CD that can be found with the Sega Saturn game "Langrisser Dramatic Edition".
Here's a pic of the full package (thanks Satakore)
If anyone can provide more informations about this CD, let us know.
About your langrisser drama 2.. it doesn't sound like a Drama album at all, so this one might not be official.