You gave me diabetes. But for real, you didn't mischaracterize them at all! I love how each of them have different interactions, and their dynamics too! The jingle jangle markiplier clip is now confirmed to be how Quetzalli became friends with Runie. Thank you for the wonderful drawing ideas too, by the way. AND SPEAKING OF RUNIE AND KANRA, I drew them. I sincerely hope I did it right, but I might post it later when it's complete. Also sorry about the yap and potential mischaracterize of your mcs, but here's how I think Xipil, Metztli, and Quetzalli would respond. Let me know if I need to correct anything!
Xipil would actually think Runie was cool, and be a bit confused with Kanra. But she'd definitely give them rocks to be their friend. She does eventually talk to him first, but she's so nervous it comes out soft. But once she realizes he's been bullied, she gets mad because she thinks he's a cool person and doesn't deserve it (he doesn't). For Kanra, Xipil would probably think Kanra likes rocks, so she'll constantly return with geodes and gems. But Xipil does dig holes in her front yard to find more. So it's like she's part mole too, because somehow she'll always find a way to dig deep. Sometimes it's awkward because she'll just pop out of a hole with rocks and covered in dirt with a blank look on her face.
Quetzalli would immediately try and get them hats too, explaining that they're very important crew mates. She'll make sure the crew mascot is a shark, and she definitely wouldn't mind if Runie got confused. She herself gets confused too, but she wouldn't notice Kanra being mean. Only when Runie points it out, but even then she forgives Kanra because despite going through so much, she can't hate Kanra. She doesn't think it's right, so she learns to sew shark plushes for her. She would consider them her best friends, because eventually she realizes that there's people who do like when she yaps. She would also ask Runie to teach her how to bake so she could give him stuff in return.
Metztli would slightly look at Runie confused, but she definitely makes him bracelets. She hopes she can try and reassure that she's nice, but she would genuinely care (platonically). She would a hundred percent insult people mean to Runie and Kanra. Metztli would make Kanra jewelry, but huff a bit. She eventually gets a bit used to it.