Honestly, it's the lack of tutorials/documentation that is leading to the issues you are mentioning. We can't answer a question related to modding if we ourselves don't know.

The Editor is something that Larian has stated several times is a Work In Progress. Unfortunately right now we're forced to rely on third party tools and file editing outside the Editor to accomplish what we want.

Regarding point 2, Main-campaign modding is talked about a lot simply because we know more about how to do that, compared to starting a mod from scratch. On the flip side, Main-campaign modding is limited in several major respects, and so far the official support from Larian has been focused on getting completely new map mods to work (the Video tutorials have almost no relevance to main-campaign modding).