I edited this question as we can only answer one question at the time.
The inference we can make from the wildly stitched block in Minnie's quit is that it is directly proportional to Minnie's state of mind. A home maker of that time and place would find comfort in stitching a quilt as a way to spend some productive and yet leisurely time.
A woman who is as tormented and abused as Minnie was did not find any comfort, even in those calming moments. She had definitely picked up the quilting to try to comfort herself, but instead she discharged her frustrations on the quilt, and this is a direct demonstration that the woman was about to lose it.