Were mrs.hales and mrs. peters action justified at the end of the play?

I think the answer to this question is based on what your definition of justice is. So, I will argue for both sides.
Mrs. Hale and Mrs. Peters are justified in covering up the evidence that would point to Mrs. Wright’s guilt. Mrs. Wright was a victim of her husband’s abuse, and she couldn’t take it any longer. Because of the patriarchal society in which these women live, Mrs. Wright’s only option to rid herself of her abuser was to murder him. Divorce or striking out on her own would not have been viable choices for Mrs. Wright. Sure, murder is wrong, but Mr. Wright got away with his wrongs for a long time—and likely would have been able to continue wronging his wife had she not killed him.
On the other hand, Mrs. Wright committed murder. Regardless of whether Mrs. Wright was a used, one could argue that she didn’t have the right to take justice into her own hands. This mentality, if allowed to flourish, leads to a lawless society in which vigilante justice could wrong innocent people. Therefore, Mrs. Hale and Mrs. Peters are obstructing justice by concealing evidence, which makes them guilty of a crime and complicit in Mrs. Wright’s felony.
As you can see, one could argue for either position to answer your question.