In case comeone needs this information, you can add your courses, communities and whatever you want to a membership. Create, maybe, something like a startup or welcome membership. After everyone is enrolled, all you have to do is ADD new things there and everyone will have access to it! It's a good walk-around this issue. Although, I would like to have a way for everybody to be enrolled in a certain membership when they register on the website (site-wide membership doesn't help here...).

In addition, when you upload them in bulk, send them a welcome email with a initial password setup link.

Agree! The only way to do this is to re-upload a csv of the names. I’ve brought this up previously as well. Bulk enrollments need to be a basic feature