I have a couple songs I want to sell people for use in their YouTube videos.

I have a couple questions.

1) Am I correct in assuming that I can't register my songs with Audiam & tunecore because they have pre-recorded tracks on them? (Audiam said I couldn't)

2) if so, how do I protect my songs from someone else trying to claim them as theirs after I sell them, if YouTube content ID isn't familiar with BIAB pre-recorded content?

This is really hanging me up.

Any advice is appreciated. Thank you!