Hi Purecyn, thanks for your answer!
If I understand you right this would solve the Problem that I cant use the “set viewtarget with blend” node inside the character BP right?
Meanwhile I managed to get it to work with the “move component to” node and some dummy cameras:
So i know can use the set view target with blend node in the level BP to blend from the characterBP`s camera to a cut scene cam, what is awesome! 
But how do I switch back to my characterBP`s cam once the cut scene is over?
Thanks in advance!