I have gotten to the point with Hugo where I've attempted to use a non-starter theme, switched up to extended, added a couple other things, and still got error messages. I am now filing that theme under "can't be arsed" rather than "you're doing it wrong." (I know I can fix him--the he in this case being Gruvbox--but there's no reason to do so. The entire point of using Somebody Else's Theme is so I don't have to muck around with the theme.)