Is it possible to use beets without it changing/fetching anything other than these two fields? i use Picard to manage all other metadata and have set up several scripts to manipulate fields that beets resets.
A good option might be import without autotagging (beet import -A) and then explicitly run the two plugins that fetch those bits of metadata (beet lyrics and beet lastgenre or similar).
great! do i then run beet write to write the tags or does it do that automatically?
That depends on your import.write configuration flag.