Name them “something.command”. They will be executed in a Terminal.
Set the dock in the lower left corner with:
defaults write com.apple.dock pinning end
and set unscaled icons [option+drag the divider].
To define an environment variable for an user (loaded at login, and not only in a shell) add it in
See http://developer.apple.com/qa/qa2001/qa1067.html for details
If you want to use Os X in English but keeping a national (i.e. European) format for dates, time and value you cannot do a sensible configuration via System Preference (unless selecting Custom as a Region and fiddling way too much with the settings).
An easy solution is to set your locale via terminal. If, for example, you want to use English but using Italian formats you can issue:
$ defaults write -g AppleLocale 'en_IT'