ZIP 210 is probably the simplest ZIP that was written after ZIP 0 was finished. It has all the sections that you’ll see defined in the ZIP Format and Structure section of ZIP 0, for what is conceptually a simple proposal.
Other ZIPs that affect coinbase, and may be useful for you to examine:
You can ignore reference implementations etc. for now.
Having seen your current OP summary, I’m now also thinking that it may be useful to have “Drawbacks” and “Alternatives” sections in some ZIPs to complement the “Rationale” section, similar to in Rust RFCs (here’s a short example). It may be useful as a summary of the community discussions that led to the ZIP. We can figure that out as we go.