if you dont know chinese, you should memorize the order of which activities you completed. the completed activity will move to bottom and next activity will go to top. so for example after subscribing to official channel, this activity will move to bottom and "share this event" activity will be on top
you can comment with emojis, but you can only comment if you registered with phone number
you dont have to do all activities, but as much as possible
yellow button already copies the code for you, if you didnt get prize, try again 12 AM china time
merchandise is likely only for china