Those all would have been excellent and appropriate red flag question responses. I saw my transferring from UCLA to my current school after my freshman year as a red flag and talked about that, as well as my seemingly average grades (I work 3 jobs to support myself so sometimes, studying has to take a back seat though I've never gotten lower than a B-).
I really think "red flag" means "anything you would like a chance to explain so we really know everything about you and your application". My transferring wasn't a bad thing at all (it was the best decision I've made yet!) but I could see the committee talking over my application and saying "why did she transfer?". I wanted to give my side of the story so they wouldn't have to imagine up reasons.
If you get a chance to interview again, make sure you address these things so that way, you get a chance to get your WHOLE story out and on the table for discussion.
Good luck! And don't worry, just because you didn't talk about these things in your first interview, it doesn't mean you won't get in! 🙂