With regard to swearing and so on - DH and I both swear like troopers, despite our best efforts not to at home. Dd's favorite songs all contain swear words, yet she's never sworn in her life (or not in my presence anyway and I've had no reports of it elsewhere). I just don't think they hold any power in our household and dd is very sensitive to the nuance of responding appropriately in different situations, so I think she'd be unlikely to swear inappropriately out in the world either.
Gosh I am glad I am not alone in this. DH and I both swear a lot more than we intend to and yet have done quite well at teaching our children not to, in part because it doesn't' get much reaction from us. Each of our older children have experimented extremely briefly as toddlers and moved on - to chiding us gently when we do.
My concerns with lyrics are much more about meaning, or air-headed lack there of, than profanity.
