They don't.
The collective noun for worshipers is a congregation of worshipers.
If they follow Jewish Law, then they are bound by the same Laws as everyone else. If they do not follow Jewish Law, they are not so bound. Reform Judaism gives its worshipers the choice of whether to follow Jewish Law if they feel that it enhances their spirituality.
No. Not all Germans are Jews and not all Jews are German. But there are German Jews, as well as Jews with many other nationalities.
no
The same as Jews everywhere.
Yes, same God for also Christians and Jews.
the same reason that all groups and societies do the same
because Jews are Jews. All Jews were seen as the same and none were treated more favourably than any others.
No. The Jews who crucified Christ are dead. It was 2,000 years ago and Jews don't live that long.
Christians and Jews believe that there is one true God. Christians and Jews pray to the same God.
The same as Jews in every other country.
The same as Jews all over the world.