How to be sure attendees' computers are ready for the workshop?
If you can, book your venue the evening before the workshop to do an installation party following these instructions. You can also use this time to invite people from your local Python and Django communities to do lightning talks.
If you can't do that, invite your coaches to meet their group online and send them these instructions. To be sure they have time to plan this online party, contact your coaches at least a week before the event.