1, you have a few Peppa Pig and hello kitty themed videos which would be breaching copyright, which would make your channel highly unlikely to be monetizable even if you asked for a review as you're using copyrighted I.P.
2, you have a channel that's made for kids, did you set your channel as made for kids? If you didn't, this is a breach of COPPA laws, and if you don't I'm not sure how that would impact a channels monetizability, but with the focus on using other brands I.P as your own, that alone would be your reason why you didn't get approved.
Use of Peppa Pig without a license would be the Duplicate content.