Hello Matt,
I glanced through that article and it appears to throw way too much info, this and that at you. I have always run my systems with a local account and I sign into my MS Account via Apps.
What you want to do is once you prepare your USB, disconnect from the Internet and boot from the flash doing a total clean install. Select custom install and delete all partitions.
Once you get to the screen to select your country, press Shift-F!0 to open a command prompt. Click in the command prompt and then type in "oobe/bypassnro" without the quotations. Hit Enter and your system will restart.
Now simply follow the normal install routine. This brings up the screen as previously click on I have no Internet. It will then prompt you for your user name. You should be fine from here.
As I mentioned, I usually sign into my MS account after I have most things setup to my preferences, for example I might use Feedback Hub to sign in, then verify account under accounts if you so want. If not simply go online and do your thing.
Have a great weekend.
Johnny