Hello,
Please, don’t post a lot of questions without numeration because we could miss something.
It would be much appreciated if you post your questions in ordered list 1)… 2) … etc.
1) How can I get rid of this part? – Go to Static Blocks and edit footer static block. Watch video tutorial on how to create footer using Static blocks https://youtu.be/gY-x4m47Duo
2) Read Contact Form 7 docs to get answer to your question https://contactform7.com/faq/i-see-green-border-response-but-i-never-receive-mail/ or contact them on the support forum if server settings are ok and server mail log is empty but you still have issues with this https://wordpress.org/support/plugin/contact-form-7/
3) Go to Pages > edit your front page > edit section that you show on the screenshot according to your needs (change elements at all or just edit element settings to change the products to show)
4) Please, follow the Contact form 7 documentation, you have a link to the docs in the email settings area if you check it http://prntscr.com/qc4xaf Add the shortcodes of the fields that you used in your contact form to necessary areas if you want to get them. Or watch video tutorials for the Contact form 7.
Regards