@Walter Hinteler,
There are formal reasons why the Parliament decided to lift the immunity:the criminal proceedings began before the three were elected to the European Parliament and the charges were "clearly unrelated" to their activities as MEPs, the decisions say.
Puigdemont said on Tuesday that this was "a sad day" for the European Parliament: "This is a clear case of political persecution." His lawyers are considering appealing the decision to the European Court of Justice.
However, the trio per se has a good chance of not being extradited:
a Brussels appeals court ruled two months ago that Lluís Puig - another former member of the Catalan regional government - does not have to be extradited. Belgian prosecutors decided not to challenge the ruling, which means Spain's request is likely to be finally rejected. The judges argued that because of the heated atmosphere, the presumption of innocence was in danger.
So it is to be expected that this will also happen here.