I hope charlotte will be friend with fl..

Well, good news: her parents want nothing to do with her. She's less likely to pick up their nasty habits.
Bad news: it is down to the staff, foremost the nanny. If the servants treat her like crap, she could go brat or Maxi from Under the Oak Tree.

So the likelihood she will like her cousins ultimately hinges on her parents keeping their paws off of her and the servants treating her kindly. With our current knowledge, she has a better shot.