When a related wikiHow article gets added to an article(such as through the link on the right sidebar) or through the Guided Editor/or even Advanced Editor, can a bot be used to cleanup and link the pages going the other way(such like the NAB tool will do with Relateds when the button for it is clicked?

It’s possible, and would be great! But it’s probably not a tool we’ll be investing time into building soon. One day though!