Option 1: Follow the same set of rules as Option 1 above, you will additionally select the region within your server that you want to player. For example, if Ridill is renamed to Bahamut, all Ridill players will be defaulted to Bahamut and then be required to select between: JP Bahamut; NA Bahamut; EU Bahamut.
It's definitely NOT going to be this. There's only going to be one bahamut one ridill, one whatever. They're not going to reuse the names because anyone can play on any server regardless of region.

The only real possibility right now given the 1.0 client is this:

All the current servers are JP servers, because that's where they were/are located. New servers will be located in other regions, both normal ones we can join and fresh start servers that you can only make a new character on.