For adversity, definitely talk about your speech impediment—I think there is a lot to be said about the skills you gained and things you've learned about yourself through that experience. I wouldn't worry about it not being super recent.
For diversity, I have mixed feelings. I think you could write a really INTERESTING essay for topic #1, but you need to do some more reflection on the skills/perspective you've gained from collecting shoes. I could SEE how it could be brushed off as a childish hobby, so you need to find a way to elevate it's importance to you (and subsequently to the reader) and work hard to connect it to YOU and your journey to becoming a physician. I would say don't write 2 because it ultimately would be about the diversity of the people you are serving, not yours, unless your teaching experience is SUPER extensive (maybe 2 gap years working for a teaching program, teaching certification, something like that ... then you could probably make a case for writing topic 2). I veto 3 because so many people have written it!
Also, happy to read drafts/help further (this goes for anyone writing secondaries!). I have a free week before med school starts and would love to give back to the community by reading/editing drafts <3