Sweet, I will use that

Blkhusk wrote:Weather I use Vimeo, YouTube or anything else.

This. Your problem would not be youtube but the copyright holders, regardless where your video is hosted.

That being said, here is a starting point for CC licensed music: http://www.newgrounds.com/audio/

These effects get applied while rendering. Pressing play does not show the rendered animation but "preview" shows roughly how the current frame would look like rendered. Yes, the real rendering happens when you export the video.