Hi,
I'm fine, thanks for asking.
I think you can remove the users if you don't use them in the configuration to set which user & user groups will be used for your site. If you check the SEBLOD site configuration and click on the 'user' icon at the bottom right of the 'options' section, you'll see which user & user groups are used.
About the tutorial, you're right, as it's a work in progress, it's not available yet.
Will we see you at the JAB in may ?
Olivier