Having Content ID claims ("matched third party content") won't effect your strike expiring after 6 months. You just can't get a second strike or it will effect it.
You don't HAVE to. You can do what you want but a Network won't likely accept you if you wish to join one if you have copyrighted materiel on your channel.So I don't need to delete the videos I have up then? Someone mentioned I won't be able to partner with those videos up...is that correct?