Mary Cooch

I would sugges you add the cohorts to groups in each course and then filter the course gradebook by group.

Hello there. You might find it useful first to read the documentation on Cohorts and also perhaps Groups 

I think currently there are some issues with locked user fields not locking -see for example MDL-36987

Hi there. No you absolutely don't need a text editor to get started using Moodle. However, you do need somewhere to host it online for you. I suggest you read through the documentation About Moodle FAQ and then ask more questions. Also - you can try it out on one of our demo sites https://moodle.org/demo/

You can use Bulk user actions as site admin to download a list of users with their usernames. As Colin says you can't see their passwords however. (If you did want to prevent them changing their password the instructions are here in the Roles FAQ documentation. )