The homonym for "total" is "toll" and the homonym for "empty" is "MT" (as in empty, referring to a truck without cargo). However, there is no homonym for the word "depression" that matches the meaning you provided.
As for the homonym for "permission," there isn't a direct homonym that matches the given meaning. However, "permit" is a synonym of "permission" and it sounds very similar. Finally, the homonym for "orally" is "aurally", which means relating to the sense of hearing.
To find homonyms, one way is to think about words that sound the same but have different meanings. Another approach is to consult resources like dictionaries, which often include homonyms and their definitions.