From reading this post I found that what appears to be a significant amount of content was changed when Mother 2 was localized as EarthBound for Western audiences. The article focuses on (possible) copyright-related changes and lists several of them.
Is there a more complete list of changes? Were the changes just due to intellectual property risks or were other changes made beyond translation? I've played the entirety of EarthBound but not Mother 2, so if there's anything that compares scenes/story elements/whatever that works for me.