A) The outfit is completely different but that's because it's impractical for her to be wearing that because she hasn't defined herself as a hero in spandex just an experiment so she might get a fighters outfit soon and even still, it's pretty BA and felt much more natural.
B) In the comic and other media Wanda's relationship always varies. Sometimes she works with him, sometimes she can't stand him, but she always has a connection if done kind to him. In the original story they actually work together to join SHIELD.
C) And she was in no way dependent on Pietro anymore than he did. They both were explained they didn't have anybody and usually they only create tention whenever magneto or how to fight for mutant kind comes into question but in a situation where neither came up it makes sense why they were so close and why she was so heart broken because they do have a close relationship. And they never show her and vision do anything more than look at each other in the movie so for you to say automatically she will be has no evidence. Not saying she will or won't but it hasn't happened yet and there is no evidence it will except that in the original avengers comics they had a relationship, but she will still just as independent. I don't ship Vision and Scarlet but I appreciate he loves how independent and passionate she is because he's trying to learn emotion and she oozes emotion which REALLY showed when h brother and only person left in her life died!
Overall; I agree there are some differences, but nothing that destroyed or even really changed or hadn't been done before. Scarlet does have a close relationship with Pietro and Joss makes reasons why they would have a close relationship, her costume changed because she isn't even Scarlet Witch yet just an experiment with ratty clothes like in X-Men Evolution and clothes she can fight in which also makes sense, and she is in no way dependent on anybody as she shows complete and utter strength.