Yes, Plesk will create the new rules once it's installed.. You can disable the default rules as they will not be disabled automatically and make sure to update the firewall rules in both inbound and outbound.
Github in layman terms is a website based file/project maintenance service used by developers where they can store and share their code with other fellow developers instead of e-mailing heavy project files every time.
For more information you can check this article: An Intro to Git and GitHub...
Plesk VPN was a component that allowed setting up an OpenVPN service on a server. However, due to consistently low installation numbers and significant resources needed to update it for compatibility with Plesk Obsidian it has been decided to stop its development
Yes, Since you say you are a beginner it will become troublesome to setup and manage the VPS. we suggest you go with managed VPS. Wherever the team will assist you with the setup and itself the team will manage your service.
Yoast SEO will upgrade meta labels and other connection components that web search tools read before demonstrating results to clients. It will also remind you to empower permalinks if your site isn't upgraded well.