Ms Giuffre, 41, who settled a sexual assault lawsuit against former Duke of York Andrew Mountbatten-Windsor, was found dead in April at her farm in Western Australia without a valid will.
Her sons, Christian and Noah Giuffre, launched a legal case in the WA Supreme Court in June amid speculation their mother's estate could be worth more than $20 million.
Court documents previously released to the media made no mention of the millions of dollars she reportedly received in legal settlements, with the value of Ms Giuffre's estate estimated to "at least ... exceed the sum of $472,000".
Christian and Noah's statement of claim says their mother owned a horse, two cars, the contents of a country home, jewellery, personal effects, shares in a company named Witty River Pty Ltd and a slice of a family trust.
She also had the potential right to receive royalties from her memoir Nobody's Girl about the abuse to which she was allegedly subjected by disgraced financier Epstein, his friend and associate Ghislaine Maxwell and the former prince when she was 17.
Mr Mountbatten-Windsor has always denied the allegations.
Ms Giuffre's former lawyer, Karrie Jean Louden, and housekeeper and carer Cheryl Mary Myers are named as defendants.
Their counterclaim said the estate was worth at least $501,000.
The case returned to court in Perth on Friday when lawyers for the parties put different views forward about whether and how Ms Giuffre's daughter, who cannot be named for legal reasons, and her ex-husband Robert Giuffre should or could join the case as plaintiffs.
Registrar Danielle Davies said the matter should be decided by a judge or master and referred the issue to the court for a hearing.
Outside the court, defence lawyer Craig Hollett ran a media pack through the day's hearing, saying it was "about whether the right parties have been joined" to the case.
"In these kinds of proceedings, it is important that all necessary parties are joined so that they have the opportunity to be heard to ventilate any issues, and so that the court can make a decision which represents all of the parties' interests," he said.
At Christian and Noah's request, the court previously appointed an administrator who has been empowered to manage Ms Giuffre's estate.
Lawyer Ian Blatchford will represent Ms Giuffre's estate in any ongoing legal cases involving her, including in the United States.
Mr Blatchford will also take charge of Ms Giuffre's interests regarding her memoir.
Ms Giuffre figured prominently in the downfall of Epstein, who was found dead in his New York jail cell in August 2019 while he awaited trial on sex trafficking charges. His death was ruled a suicide.
When confirming Ms Giuffre's death in April, Ms Louden said she was honoured to have worked with someone who was "so strong and powerful and willing to advocate for victims of sexual abuse".
A further case management hearing over the estate will be held on May 1.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
Lifeline 13 11 14
beyondblue 1300 22 4636
