I know rule 1 says "No using stash/artisans/vendors", does that include repairing? I'm goofing around on Master NG for fun and my items have broken, so that's why I was wondering.

The rule comes from the fact that you run at Normal or Hard for the first some minutes where the Items shouldn't broke at all but if you want to do a Master NG run you can repair Items

Btw, why no vendors? You can quite often buy better items there for NG run.

because you have your SC or HC Gold wich you won't have when you start a complete new game

True. Forgot about gold :)