what special abilities did the crewmen think the albatross had?

THe albatross was considered a good omen. The mariners felt the albatross was their guide to avoid certain rough seas and storms. They felt the albatross would bring them to calm waters and finally safe harbour.

Also, I'm not sure if the albatross actually represented a Christ-figure to the mariners but Coleridge certainly goes down that path with this bird.