I’d add one thing to number 5: Writing good copy is crucial not just for your Title/snippet, but for your whole page, especially your landing page. You want people to stay on your page for a while and (hopefully) even navigate to other pages you have. Google looks at bounce rate and where they go after they hit your page. Learning to write good copy can not only increase conversion (if you’re selling something) but make your content more impactful and engaging. There are free books at most libraries or online to help.

SEO is also about making your search engine result relevant to the user's search query so more people click the result when it is shown in search. In this process, snippets of text and meta data are optimized to ensure your snippet of information is appealing in the context of the search query to obtain a high CTR (click through rate) from search results.
When referring to the homepage, a trailing slash after the hostname is optional since it leads to the same content ("https://example.com/" is the same as "https://example.com"). For the path and filename, a trailing slash would be seen as a different URL (signaling either a file or a directory), for example, "https://example.com/fish" is not the same as "https://example.com/fish/".
Take the 10 pillar topics you came up with in Step 1 and create a web page for each one that outlines the topic at a high level -- using the long-tail keywords you came up with for each cluster in Step 2. A pillar page on SEO, for example, can describe SEO in brief sections that introduce keyword research, image optimization, SEO strategy, and other subtopics as they are identified. Think of each pillar page as a table of contents, where you're briefing your readers on subtopics you'll elaborate on in blog posts.
Hey Ted, thanks for the great questions! The peak times refer to your particular time zone, if you are targeting an audience that resides in the same zone as you. You can also use tools to find out when most of your audience is online. For example, Facebook has this built into their Page Insights. For Twitter, you can use https://followerwonk.com/. Many social posting tools also offer this functionality.