I've done the renamed players for Treviso, Zebre, Newport, Cardiff, Opsreys and Scarlets. All the Guiness Pro12 players are from 2012-2013 season; without those who have moved to other clubs.

Haven't managed to explore the French leagues at all yet, (it would be good if someone more knowledgeable than a FIFA editor help with this...), but there is already a duplicate: Alberto Di Bernardo plays for both Bourgoin and Treviso...