I assume that you do not have controlled groups.
(1) I would reset a selected set of machines (let say a 100) to group properties, every day, to disperse load on servers.
(2) Old clients should work as nothing changed.
(3) No re-encryption would occur during client upgrade.
(4) Manage languages via fileset setting scripts (remove and add different filesets). That could be also used for item (1).
(5) You can do selective USB fixes if you know BIOS details. Certain sections in ini file will apply.
Thanks for the quick answer.
(3) Can you maybe explain more about the usage of scripts to change language?
(5) The thing is we want the whole notebooks from a certain vendor to work this way, that way when we have new versions of notebooks(ie new bios update) we dont have to create always a new installation set with the notebook's detail.
(3) sbadmcl -command:SetMachineFileGroups
(5) find out what is "static" in vendor BIOS information and use that for exclusion.