I find it hard to define what an Everton legend is. I don't think there are many. You have the obvious (Dixie Dean - top scorer), the successful (Catterick and Kendall), the long-lasting (Ratcliffe, Lyons, Southall, Labone, Sagar), yet I look at the list and see the likes of Lawton, Farrell, Young, Ball and Watson missing and I can't quite define why they should be there.
I don't think Ferguson or Cahill (or Neville - he's been the longest serving captain for decades) can be considered legends to be honest. Sometimes, people accomplish great feats playing for the club but their most playing career takes some of the reverence away.