I believe that Olver is Gaidal Cain because in tFoH Birgitte says "Gaidal is out there, somwhere, an infant, or even a young boy." Also when Nynaeve saw Gaidal in Tel'aran'rhiod she described him as one of the ugliest man she had ever seen. Olver is also described as ugly. He also seems young and wilfull like a young hero would be.