Hi, Not certain about B777 - but the way I believe it works is:
Fail -Operational is when you have a second system able to take over if the first system fails:
Case 1). 2 autopilots available for autoland - but something wrong with the Roll Out system so the Pilot may have to complete the Roll Out if the primary system fails.
Case 2). 2 Autopilots working and either is capable of Auto Land and Auto Roll Out.