It is not clear if you are asking about the Premier Pro CC that is rented monthly or the Premiere Elements that you buy once.
I know nothing about Premier Pro CC. However, I can tell you that it is easy to add and control music tracks in Premiere Elements. Additionally, it has built in tools for creating YouTube music.
First, there is a clever music generation system that will match the length of your video. But it is limited to 30 or 40 choices. However, just as you can add video or image files, you can add any MP3 or WAV music files from any source that you have rights to use. There are more online sources for music intended for video than I can count. A lot is free and a lot charge for the rights to use it.
Since you mentioned iTunes, SoundCloud and Amazon, you should know that those can be very serious about their copy protection and licensing rights. Their tracks can contain blocks for use in personal videos.
I was asking about Premiere Elements 15, sorry. I know about copyright, I was just wondering if it was possible. You seemed to have answered my question though so thank you!
If you buy Premier Elements and need some tips for adding music tracks, please post a request here. It is quite easy.