Mr Dayimani has previously told the court that his client is not psychologically fit to stand trial because of a brain tumour.
Mngeni looked thin and trembled slightly.
The judge asked if there was a third accused who should be on the court roll, referring to Mrs Dewani's husband, British businessman Shrien Dewani.
He was told the state will add him as an accused only when he is mentally fit.
A trial date was set for July 30.
An order for Dewani's extradition was signed by Home Secretary Theresa May last September, but the High Court temporarily halted the extradition on mental health grounds, saying it would be "unjust and oppressive".
He will be extradited to South Africa as soon as he is fit.
Dewani is being treated in a psychiatric hospital in Bristol.
Mngeni and Qwabe face charges of kidnapping, robbery with aggravating circumstances, murder, and two counts relating to the illegal possession of a firearm and ammunition.