I have trouble with #1 above also, and have for a while now. Sometimes my lists are there, and sometimes they are not, as if I had never created lists. Just some dashes appear and I cannot add my bookmark to a list. I'm just about always on Firefox.
I have a student group, and in the teacher console, if I click on "activated" members, none are listed. Yet, several have successfully joined the group and uploaded the toolbar, and one has begun to share bookmarks.
I have a class working through a Diigo education account. Sometimes sticky notes appear and sometimes they do not. I think the same is true of highlighting. It varies from time to time, but also between screens when I am viewing the same person's work in two places at the same time.
Very confusing in trying to give credit for their efforts.