Yes, but it actually sounds quite formal to me. The most neutral way to end an email in English--and the one I use most often--would be "Thank you". Likewise, the most neutral way to start an email would be "Hi" or "Hello". As a university professor, I can tell you that I would find an email beginning in "Hi Chris" and ending in "Thank you" perfectly appropriate. (Some professors don't like to be called by their first names, though)...

I would use 'Kind regards' as a semi-formal sign-off, but that is just a matter of personal preference.

Yes, it's correct, but to me it sounds quite personal. I wouldn't use this in a professional email.

Yes, so it's good to show respect.

There is a lot of variety depending on purpose (professional/personal), age, and whether what you have written is "letter-like". If it's professional and you're asking for something, end with 'Thank you' and the name you want them to use for you. In my experience, shorter professional emails between people who already know each other usually don't have any closing. 'Kindest regards' suggests to me personal, older and letter-like.