If he has a licence to use it i'm sure you would need one too? The other people, you need to make sure they actually are the creators of absolutely everything in the tracks, someone can say it's free but they might of taken someones work and added that to the song (not saying anyone did that) i'd double check on that and after 30 days and you are sure, apply to social blade and see what happens, I can't say you will get partnered as there is a slight chance you may get denied due to suspission of copyrighted music, if you have a licence for them you will get away with it