9-13 looks good to me. Below is green, above looks like the insides are getting too much brown already.

Stop trolling. Green bananas are disgusting.

Multiple. But a very penetrant one is the Miss Marple theme: https://www.youtube.com/watch?v=J9ILsxqdK7E I keep remembering the melody and playing it in my head without noticing that it’s this.

Take 5 by Dave Brubeck

Oh so that’s what it’s called!

AFAIK, no.

It depends on the laws in your country. And IANAL.

But, usually, as long as you don’t publish (or play publicly), it’s fine. The lyrics, the arrangement, as well as the melody, and everything else, are subject to copyright. So if you want to publish a cover, you need permission to use the relevant parts. The usual exceptions of your country’s copyright law, like fair use in the usa, apply of course. But I haven’t yet seen anything that would allow covers.

Also, from what I’ve heard of people making covers, they usually first have to look if the original author has allowed covers. Often they allow non-commercial covers only, unless asked. On youtube, copyright is also not handled very strictly, and it has a feature where the original author can claim the copyright offender’s revenues, so the video stays online, but the money doesn’t (or only partially) goes to the coverer.

I’ve recently started listening more to STPR and similar boygroups. It’s kinda stupid, but catchy and fun. Examples: 1 2 3

I shower in the shower.