Thank you for the kind words about Maizie! She's bounced back fairly well from losing her father (the benefit of youth!) but there was definitely a period of shock and mourning, which Charlotte might have experienced herself, since many of the residents of the shelter were rocked by Gray's death. (Has anyone explained to you yet that he was killed by the Capitol's patrolmen? Most of Austin believes that the Hellhounds were responsible, since that's the official story from the Capitol, but the LBJ knows the truth. Hence why they're aligned more closely with a group of raiders than the city's current government.)
Maizie and Olivia aren't really keeping their relationship a secret at this point, so I don't think it would be a stretch to say that Charlotte would know about it. And I'm glad to hear that you think Charlotte and Maizie would get along! Maizie would definitely be up for learning whatever Charlotte wanted to show her, just to expand her general knowledge, and she would definitely be grateful if Charlotte didn't hold back with her.