Williams was denied bail to enable police to continue their investigation.
He is due back in court on June 10 to enter pleas to the fresh charges.
The couple, who live in Cambridge, earlier pleaded not guilty to three representative joint charges, one each of indecent assault, unlawful sexual connection and the rape of an 8-year-old girl.
Police say these offences were allegedly committed at a Bay of Plenty camping ground this year.
Police allege Rose groomed the young girls to build trust with them, before encouraging them to engage in sexual activities with Williams, her partner of 10 years.
Lawyer Olivia Brittain entered not guilty pleas to the two fresh charges for Rose and told Judge David Cameron that Rose elected trial by jury.
Judge Cameron remanded Rose on bail to next appear at a case review hearing on July 1.
Laken is well known in equestrian circles in Cambridge and Williams is a regional field manager for a tiling company.