Personally, I wouldn't wait as long as Hand Solo before landing.
The pax are told well in advance of the landing time and the seatbelt sign comes on well before landing (10 or 20 minutes).
As for the cabin crew, as far as I'm concerned you discharge your duty of care by pointing out to the pax that they should be seated as you are about to land. After that it is the personal responsibility of the pax for their safety.
I would not go-around and burn an extra 2-3 tonnes of fuel on a 747 for someone on the loo. As you say, the go-around manoeuvre itself with sudden pitch and power changes can cause someone to fall over and may be more damaging to them than landing.
So in summary, tell the pax to return to their seat and stay safe yourself, leave the rest to fate.