Can all students in a group see their group's submission in an assignment?

Yes, they can.

1. The student who submits on behalf of the group has the option of adding a comment when submitting. This comment can be seen by the group members.
2. Submission details shows the latest file uploaded.
3. Every version submitted is stored in the group's files area. These cannot be deleted by the students.
4. All students in the group can see the submission, download the submission and see teacher's feedback on the submission.

Instructors will see the latest file uploaded in SpeedGrader. The instructor can also access previous submissions, if any, via a drop-down list.