Thank you so much, @bbennett2!
I tried the two GET functions you mentioned. Here is my quick notes and hope it will help more people potentially.
1. Using User Activity Stream I get my own activity stream or someone's when I have their access token. This is more than I expect so I'm glad that I tried it. However, I need others' activities and I don't have their tokens. I was wondering if I miss any method to get it.
/api/v1/users/self/activity_stream?access_token=[access_token]
-> I get the activity stream of the token's owner only
/api/v1/users/[student's user_id]/activity_stream?access_token=[teacher's access_token]
-> error 404
2. Using Analytics I get everyone's discussion forum visit counts. Yay! It aggregates the counts to certain degree (see picture below) but I can start from here. I need to validate it somehow.
api/v1/courses/[course_id]/analytics/users/[user_id]/activity?access_token=[teacher's access token]
