I was wondering if you could answer this question to the best of your knowledge;
Does a wife have obligations to her in-laws? If so, what are they and does she get sinned if she decides to not have a close relationship due to them disrespecting her and mistreating her?

Her obligations to her in laws are the same as to any other believers, though if they are living together then those obligations on both sides to maintain a level of decency in the house. If that is not possible at all due to one side or another being unreasonable then there is no obligation and the husband needs to intervene to get a solution.