Irina - let's return to t your original question about German folk dances. They are still played in rural areas by interested musicians, and rural people are dancing to the tunes. Nevertheless these keeping alive the dances is a matter not of the average people but of interested people forming dancing circles in the villages.
When the dances were written down by the collectors, they often noted only the tunes. If you find a piano setting, be glad - here you have the harmonies to play other voices.
The polyphone settings are often done by the musicians themselves; the instruments are varying depending on what's just at hand. You find violins, trumpets, clarinets, accordeons, guitars and for the bass strings or euphonium.
Some of the more popular dances also have lyrics in the form of short ditties which can be sung by the spectators.
In the Alps you also find hammered dulcimers and zithers with the music.

Wilfried