I think so. Lottie really cares about Tia, and makes sure she's ok. When Tia ends up being with the man she liked, she isn't angry - she's happy for her.

Eudora? "Go have sex with a man. I want grandkids."
Mama Odie? Nothing.
Evangeline is a star, but Lottie genuinely cares for Tia. When Tiana tripped and ruined the food, I expected Lottie to get all whiny and complain about how she was going to get her man. I was really shocked and happy when she left Naveen, helped her friend, got her a new dress, and didn't yell about the beignets at all.

Definitely Charlotte. Not only did she do the things metions in the comments above me, she was also the one who gave Tiana enough money to buy that place she wanted.