can be Unity (UM for Domino) installed with different accounts than recommended in documentation (UnityAdmin, UnityInstall and UnitySvc)? Due to the region naming convention, we need country specific names, for example UK_01_UnityAdmin, because default names can cause conflict in common AD structure.
Yes, you can choose how you want to name them. These are simply suggestions that Cisco provides as most people just simply follow the guide. As long as you can differentiate them when running Permissions Wizard and MSCW, you're good to go:
"We suggest that you use the following names for the accounts:"
Hope that helps,