alexban limits are in my company part b.
fruitbatflyer according to the FCTM "The use of dual autopilots with an engine inoperative is not authorised"
If you were to make an approach with one engine at idle you are as good as single engine but following the letter of the book if not the intent, and I believe the sim will fly that quite well.
I am in the sim next week and will try to have a look at an approach with only one auto pilot and report back. I think it will be like a dual channel approach with a fail in the flare mode, no danger of aquaplaning off one of those