1.I don't have a favorite, but some pop punk bands I like include Fall Out Boy, The All-American Rejects, The Starting Line, Cartel, Saves the Day, Sherwood, The Academy Is..., The Ataris, blink-182, Box Car Racer, Acceptance, Say Anything, and The Format. I'm sure I forgot some, but those are definitely some pop punk bands I enjoy listening to. Also, I don't know if every single one of those bands I mentioned is considered pop punk, so yeah.
2. Don't have an absolute favorite, but here are some tracks I love:
Saturday, Dead on Arrival - Fall Out Boy
She Doesn't Get It, Dog Problems, The First Single - The Format
Bedroom Talk - The Starting Line
Teasing to Please (Left Side, Strong Side) - Cute Is What We Aim For
The Boys of Summer - The Ataris
Losing Control, Anything Is Possible - This Providence
The Letter, So Contagious - Acceptance
I Loved the Way She Said L.A., Those Days You Felt Alive - Spitalfield
3.Don't really watch music videos, so I wouldn't know.
4. Any of the bands I mentioned.
5. It's enjoyable to listen to, especially in your adolescent years since the songs usually have to do with teenage feelings (very relatable).