Its obvious that Sammael sent the gholam in Ebou Dar...Carridin told him about seeing Mat Cauthon, and (I think Elayne and Nynaeve) and he said 'I'll send an agent' or something. (I don't have the book at the time.) Also, we know that the way gholam would have survived the Breaking was in a stasis box, whatever that is. And once again, we know that Sammael has found various stasis boxes (i.e. his meeting with Graendal). Maybe the gholam was in the stasis boxes that he found. Where does this tie into Fel? Well, because we have heard of no other Forsaken with Gholam, we can temporarily assume that Sammael sent the gholam to Fel, until we get further information.