A loit of times i find my self writing new contributions to movies which already excists in the database, except this is a different release with differt subtitles, cover etc. There should be a possiubility to copy actors, data etc from excisting contributions. Maybe it is, and I havent found it... Or possibly getting the actors from imdb....

You can download the same movie that is already in the DB to your local DB. The you can use the change UPC feature.  Then you can update the new profile with the features, coverscans, audiotracks and ect for the release you have.

The cast and crew you will need to verify that the same cast and crew matches the release credits you have.  Sometimes their may be differences or the profile you downloaded may have bad data that still needs correction.