Some of them may have their hidden ability iirc.Do the visiting wild Pokemon from Poke Pelago have anything special or they are just like any other wild Pokemon you can encounter?
Yes, they are. But your sync must be on the field in order to affect the S.O.S pokemon, so that's a negative for your second question.Are SOS mons affected by Synchronizers? Can I have a fainted Synchronizer and have the SOS mons have a chance for the nature?