I look forward to hearing responses on this. We have tried it on point 1 and found it quite difficult. The main problem is in updating materials. You can divide the cohorts into groups, but if you remove an assignment and replace it with another one it disappears for the earlier group. We got over this by using "groupings", but even then it is conceptually difficult and needs to be carefully used. As the different cohorts go through at the same pace, we just had to use groups for the discussions and that worked fine.