Migrate to Different Droplet, Enable Git and Mail Sending

We're a small, new company that auctions items online. We need help in using best practices to keep our site secure and always running. Our website is called [login to view URL] Present state: We have only one production/ testing/ everything server, and we edit files directly with no version control or Git repository. Yahoo and Hotmail also do not receive valid emails from us and return/ bounce them to us. Future state: 1. We need to be using Git system (please help me choose a Git system and teach me the basics of using it). 2. Production server must be in a separate droplet from testing. Https://[login to view URL] must be on a separate droplet from [login to view URL] and alpha.automart.ph. Entire DB and contents must be migrated. 3. Since currently [login to view URL] is already LIVE and CUSTOMER FACING, entire present site must redirect to its counterpart in [login to view URL] ... example: [login to view URL] must redirect to the exact same auction in [login to view URL] . Note: if this will be too difficult, we can redirect all from [login to view URL]* to [login to view URL] . Important that there should be no 404s or other broken links. 5. Yahoo, Google and Hotmail must receive our emails and not mark them as spam or worse bounce/ return them. Suggested tasks based on Yahoo which may or may not solve the problem: DKIM authentication Publish reverse DNS records BE Can-Spam DMARC Compliant Establish Compliant Feedback loop w Yahoo, Hotmail and Gmail Limit messages to send per SMTP connection to 20 basically everything relevant here: [login to view URL] Etc that can help to solve problem 6. [login to view URL] may reside in same droplet as [login to view URL] to conserve resources for now. Restrictions: Cut-over should be Wednesday 12nn Philippines Time Droplet(s) must have appropriate firewalls, SSH access, etc. Must maintain SSL Droplet must be able to shut down/ powercycle and startup again Auto-backup must be enabled Give me all access/ passwords/ etc. All other things I'm not thinking about yet, please help me to think about them. I currently use Zoho to host some of my emails (my_name@[login to view URL]) This shouldn't change. We use the same email address (no-reply@[login to view URL]) for mailchimp as well as these email addresses. This should not change