Can you edit Mii profile?

I've been wanting to add my birthday and creator information, but it's blanked out. I have "Dog's or Cats", "Hobby" and "Dream" answered but it won't let me answer the other two questions. I see other people have them answered through StreetPass. How do you unlock those questions?

I can't, there's no option to. It will let me edit the question I already answered in the Plaza, but not the two at the bottom.

In Mii Maker, there are option to modify these but when I do they do not appear in the Plaza. My "Creator" is blank. Is this only because it's mine? Do other people get to see my name? I'm all for sharing as much about myself as possibly as I use my greeting to direct people to my YouTube channel. Also, do you know if there is a way to for people to see the greeting at any time, outside of a personal meeting? That way I can hopefully get them to write down my shortened URL. Thanks.