When I import my tracks to Recordbox 7, then into Lexicon to analyze and find additional tag data, genre, cover art, etc. and sync it back to Recordbox, does this affect the source files where the music is actually stored? (iCloud in my case). What happens if I move my tracks to another laptop, hard drive, or into iTunes or whatever? Will all of this data - cover art, bpm, album name, cleaned track names, etc. be retained in the source files? Thank you!
Generally it does not affect the music files, with the exception of cover art. Cover art is stored in the music file so finding that will modify the music files.
Lexicon does not write any info like artists or titles to your files (ID3 tags) by default. If you do want that, you can right click the tracks → Use → Write Tags To File