Best answer by djraveinpeace
Thank for visiting the help forums :)
To answer the first part of your query, if you delete a track then that track will disappear from any playlist it has been added to.
Im not entirely sure exactly what you mean in the second part of your query..playlists themselves don't really gain any stats other than people liking or sharing the playlist..any plays of a track within a playlist is counted towards that tracks play stats, if the track was removed from the playlist but not deleted, it would still retain its stats, in the same way a track that already has play stats is then added to a playlist, that track still retains whatever plays it has already gained.
Hope this helps, but any further queries please don't hesitate to get back in touch.