What technical users are provided and required by Satellite 6

Issue

• Our Test Setup with Satellite 6 has different accounts created during installation as Satellite 6.1 has.
• We normally reserve technical user ID's in our Environment to assign specific and globally defined UID's.
• Is it possible/supported to predefined technical users and groups.
• During coming upgrades, will the installer handle group member changes.
• In our test environment we found the user gutterball created in a reserved ID Range.
• We would like to prevent different technical users with same ID's.
• What technical users are being created during Satellite 6 installation.
• Can I predefine UID's for users created during Satellite 6 installation.