Looks like you scored a bunch of nice parts from a decent bicycle.. As far as the rear derailleur being a DuoPar Eco, I don't think it is.
VeloBase.com - Component: Huret Duopar ECO (Version 1) or
VeloBase.com - Component: Sachs Huret DuoPar Eco.
IIRC all the Duopar had longer cages. The titanium Duopar on my Davidson tandem is a thing of beauty (at least for a derailleur), though they have a reputation for being unreliable.