I agree that it sounds a bit strange. "Those happened yesterday" seems more natural, perhaps because "yesterday" implies some distance (in time) that would make "those" preferable to "these" in English (though of course the Turkish uses bunlar rather than şunlar or onlar ).
Hello, Mariane and Dorkykong. You see that my post was in response to DarynKJohn. I agree with him and you (Dorkykong) that the English sounds more natural if we include "things." It's also true that "these" and "those" can sometimes stand on their own as subjects. I'm happy enough with the English translation as given. If I were part of the conversation myself, I would probably include "things." It looks like the Turkish pronoun stands on its own a little better than the English ones, at least in this example.