I don't see why not. If you can extradite a person from another country in a case, there should be no reason that you can't sue them. Since you are in another country, you'll have to either travel to the country of the defendant(s) or have someone act on your behalf in that country (bring up the lawsuit, completing paperwork etc)
Sure. Like people suing people from America, which is common (maybe food products etc.). But you can't sue anyone here if you live here.
