Amazing writeup. Bought my Pi 3 on Amazon yesterday afternoon, got it same day shipping, and by last night followed your instructions with it all setup. I have yet to test it, but everything went perfect.
Question about Samba. Following your instructions, it gave my Windows 7 machine (which previously I had my external HDD connected to it, and since hooked it straight to the Pi) immediately read/write to the network connected external. This also would give anyone connected on my home network access to read/write as well, correct? I would prefer my machine being the authority on adding/removing files to the external, and nobody elses in the household. How would I do that with Samba and your instructions?
Also, the Pi 3 is the 1 GB version, and I read elsewhere to decrease the GPU memory to 8MB (16 was the lowest mine would go) because of booting into the command prompt and not startx. Is the reason for this because the PI itself isn’t displaying video, but outputting it?