Thank you for the question.
I would suggest that you follow the Nemeth rules for matrices and keep the closing enlarged grouping signs unspaced from at least one entry in the right-most column. Then the column separation line under "NorthClean" will extend beyond the matrix.
As for dot 5s between columns, since the Nemeth rules for a matrix do not include them, I would say you should not include them.
So, I would not move the closing enlarged brackets so they are outside the column. And I would not use guide dots between the columns of your matrix. My thinking here is that it's best to follow the Nemeth rules inside the matrix and apply the table rules outside the matrix as far as is necessary.
Please do let me know if you have further questions.