If players from those national sides are registered to clubs already, and then their national teams decided to join domestic leagues in surrounding countries, they would effectively be playing for two clubs, which I'm sure would be against UEFA reg's.
You misunderstand. I'm not saying that all Faroese players would have to play for "Faroe Islands FC". There would be a shift in status, so that Faroe Islands for example would join a league and be given the option of signing players from wherever they wish. A grace period of say 10 years would be given to prevent them from being relegated due to the fact they are starting from scratch as a club.