Fantastic guide, thank you very much Mr. Bookholt!
As with the above commenter, I accidentally mistook the fan's standoff for a screw and removed it while removing the fan. Also the top right fan screw's standoff came out along with it. I edited the guide with a note on this.
While replacing the antenna, it wasn't immediately clear why the screws weren't lining up, until I realized that two of the screws were in the (otherwise free-floating but for the back grommets) hard drive, I also added a note on that.