1. As of the new version, has this list been expanded on?:

TITLE -> Track Title
ALBUM -> Album Title
TRACKNUMBER -> only used for arranging tracks in correct order
ARTIST -> Artist
DESCRIPTION -> Album Notes if same text in all tracks. Otherwise, individual track Notes
COMMENT -> same as DESCRIPTION
GENRE -> Genre
DATE -> Release Date
COMPOSER -> Composer
BPM -> BPM
LABEL -> Label
LYRICS -> Lyrics
PERFORMER -> currently not imported, in future will go into performance credits
CONDUCTOR -> currently not imported, in future will go into performance credits
LYRICIST -> currently not imported, in future will go into performance credits

2. Are there any plans for this in the future?:

CATALOG# -> REFERENCE#