Using Group Policy to set Domain client language / regionalization

This is a User config, you needed to have this apply to your environment based on the computer, not the user, so you'll need to set the Group Policy loopback processing. That is found under:

Computer Configuration > Administrative Templates > System > Group Policy > User Group Policy Loopback Processing Mode 

To set the policy for language and regional settings. In the console tree under User Configuration > Preferences > Control Panel Settings. Right-click the Regional Options > New > Regional Options

http://technet.microsoft.com/en-us/library/cc754020.aspx

To answer your second question about enforcing. I would create an OU for your Kiosk workstations. Under that I would create an OU for each Region. I would put each of your workstations in the specific region container. That way you can apply group policy settings to your Kiosk OU and it will apply to the Region OU as well. Then you can manage each of the regional options inside your Region OU

Kiosk
   |-Italy
   |-Russia
   |-Spain
   |-USA

Group policy should be able to set you up with that. You can places the workstations in OUs based on locale, then attach a GP to each one. Look under User Configuration > Preferences > Control Panel Settings > Regional Options. Once there, on the right side, select More Actions > New > Regional Settings and you can set the options there for language, numbers, currency, etc.