Perfectly, that's how it was designed. It was designed at Michigan State University with NSF funding to perfectly align with the NCTM standards and then matched to the Common Core standards in their second edition.
Question 2:
Students that are behind need math intervention, including math lab with instruction aide support. The CMP was designed for student to be able to gain conceptual understanding through problem solving which should also help them build those skills from a conceptual level - because the CMP is so hands-on, it was designed to be accessible to students.
Question 3:
The application sets are designed to give students opportunities to practice their skills and also verify that they have an individual understanding of the skills because they often learn skills in a group setting but need to know how to complete problems by themselves.
Question 4:
Group roles are regularly assigned and rotated within their group. The teacher also has to be good about actively monitoring the students and helping to guide their exploration. Once the expectations are established, the majority of the students do not have issues. Troubled students are targeted, both by their seating arrangement and group placement for better supervision.
The ultimate accountability will be of course completion of the required task in the required amount of time. Individuals also have homework to complete.
The teacher's guide comes with excellent guidance for launching and closing the exploration periods, including checking for understanding and methods for ensuring that all group created algorithms produce correct results. Regular homework and quizzes also assist with assessing student understanding.