Good of you to compare SEO strategies to a battlefield. Tactics and strategy are two very confusing words when put together in the same boat. You are right. Every company feeds on different strategies to hope for the one and only outcome: SUCCESS. Every company should make realistic and achievable goals but what about their vision? Companies stand out from others when they do things in a different and efficient manner. But, I love your ideas and can’t wait to put my thinking hat on and start the considerations.
Although this is a step-by-step series, everyone's methods will (and should) vary, so it really depends on how much time you think it will take (if you're billing hourly). What tools do you have at your disposal vs. how much researching for information will you have to do on your own? Will you have to pay for research reports or companies? Do you pay a monthly service for data or research?
Lastly, it's important to remember that paralysis by over-thinking is a real issue some struggle with. There's no pill for it (yet). Predicting perfection is a fool's errand. Get as close as you can within a reasonable timeframe, and prepare for future iteration. If you're traveling through your plan and determine a soft spot at any time, simply pivot. It's many hours of upfront work to get your strategy built, but it's not too hard to tweak as you go.