The autoland function is build into both autopilots,but due to the FAA requirements the autoland is not certified in single channel use.The touchdown is not guaranteed to happen in the touchdown zone using Sch,and you should try ,it in the sim sometimes.It's not so precise like a dual channel flare,a bit hesitating,I think.
I won't try it in real life,you'll have no crosscheck of the autopilot during most critical part of landing,no backtrim at 400',Raltimeters crosscheck,...and you are not authorized to do it.
We do something else here,on every ILS app ,we select both AP on.When sure of landing ,disconnect ,and land manually.If any doubts,for ex late clearance,if bellow 400',leave it on and autoland.
If you think you'll gone need autoland on Sch,I suggest Go around and select both Ap on the second app,or divert somewhere where you can legally land.Simple as that.
Fly safe