3) Fail Passive is still full autoland, no need for manual landing. Under CAT III conditions, autolands are not possible anyhow. (without going into too much of a detail)
What on eatrh do you mean??
What is the point of an (all be it degraded) autoland system if you can't use it when you bloody need it??
In our airline Cat 3 dual is Cat IIIb and Cat 3 single is Cat IIIa