I have a few theories about Hans. I've been having a few ideas ever since I watched nagyelo back in November. I have two theories.

Theory #1
Don't hate me, but I had to bring this up once I thought about it. Seems like a lot of people think Elsa and Anna look like Rapunzel. But when you really give it a look, Hans looks like Rapunzel and Eugene combined. Hans has Eugene's jawline, a combination of both their noses, his chin, Eugene's forehead, Rapunzel's eyes, Eugene's eyebrow shape, Rapunzel's lip shape and rounder cheeks, Rapunzel's thick eyelashes, and Eugene's thing of having a little bit of facial hair.
Hans is a Prince of the Southern Isles. In the Northern Hemisphere, south means warmer. I don't know about you, but Corona looks warmer and sunnier than Arendelle. And who's to say Corona doesn't have other islands nearby that we can't see in the movie?
I hope I don't see comments about how "Rapunzel and Eugene would never raise someone like Hans", because if it was possible for someone like Gothel to raise Rapunzel, then the same may be possible for Rapunzel and Eugene.
We don't see much of Rapunzel and Eugene, they only appeared for two seconds. For all we know, they could've aged.

Theory #2
This theory goes a little like this. The reason Rapunzel is there at Elsa's coronation is because they are family related sa pamamagitan ng blood. Now this begs the question, why wouldn't Anna have recognized Rapunzel flat out when she almost literally ran full steam into them? Easy enough. Rapunzel wasn't reunited with her birth family until she was 18, and probably didn't marry Eugene until she was 19 or 20. Now, if Elsa and Anna's mother was related to reyna Corona, Rapunzel's mother would have invited her sister and her sister's husband to Rapunzel and Eugene's wedding, which they would have had to travel sa pamamagitan ng ship....only the ship never made it having sunk during a powerful storm at sea. So, since neither Elsa or Anna were really permitted beyond the palace walls they would have had no idea who Rapunzel was or looked like (since she'd been missing for around 18 years). If the timeline fits, Rapunzel was probably 22 or 23 during her cameo, a taon or two older than Elsa.
Now comes the madami complicated Hans. My theory on his origins is similar to the first theory. He did, in fact, come from somewhere within Rapunzel's kingdom or one close by. I'd like to think that his last name is possibly Stabbington (after the two twin thugs Mother Gothel hires to scare Rapunzel back to her near the end of the film). Hans spoke about having 12 older brothers, so what's not to say two of those brothers (princes sa pamamagitan ng all right) turned to a life of crime because of either boredom or attention seeking. And he even looks like the twins, if not a little madami on the good looking side.