In theory using the first song you mentioned (even if it is not profit motivated) would at least require written permission to use. You could claim "fair use," but if the record label actually filed a lawsuit it would be hard to argue "fair use." However, the likelihood that you would have a lawsuit filed against you for using a song on your personal website is very low since record labels are more concerned with the illegal sale and distribution of their tracks. In fact you might actually be in better shape if you do upload your video to YouTube since often record labels will claim copyright on your video so you cant monetize it, but allow you to keep it up, then you could just embed that into your website and know you are safe from any legal stuff (if they don't take it down from YouTube).
You can take a look at this site for more general copyright rules.
https://www.copyright.com/blog/music-licensing-fair-use/
As for Apple's sounds included in iMovie, it appears that they are royalty free and you can use them in your projects. Please take a look at this discussion for more information.
Is iMovie music copyright free - Apple Community