Hi Ramo,
With regard to the mp3 to flac conversion, this would not be of any benefit to you. The original wav to mp3 compression will have removed some of the music content (in order to achieve the mp3 compression) so that data is gone forever. Converting the mp3 tracks to flac won't bring that lost data back; what you would have is a flac file which is running at mp3 quality.
Re the classical tracks listing, there is a well-infomed thread on this topic in this forum posted on 27/06/20. If you search for 'B2 for classical collections?' (without the quotes), perhaps this will help you.
Regards,
Peter.