Former Yorkshire bowling coach Richard Pyrah is the latest person to withdraw from the disciplinary process relating to allegations of historical racism at the county.
Yorkshire have admitted four amended charges and will not appear, while ex-England batter Gary Ballance admitted liability in response to his charge and will not participate.
Yorkshire and the individuals were charged by the ECB with bringing the game into disrepute, over allegations made by former all-rounder Azeem Rafiq.
Former head coach Andrew Gale said in June he was "not willing to engage" in the process, and last week ex-Yorkshire players Matthew Hoggard, Tim Bresnan and John Blain withdrew.
The England and Wales Cricket Board's (ECB) Cricket Disciplinary Commission will hear the charges in their absence from 1-9 March. A hearing to decide sanctions will take place at a later date.
Vaughan "completely and categorically denies" allegations he made a racist comment to a group of Asian players.
In September Gale and 39-year-old Pyrah agreed compensation over a claim for unfair dismissal with Yorkshire following their sackings in 2021.
Yorkshire's charges include "a failure to address systemic use of racist and/or discriminatory language over a prolonged period and a failure to take adequate action in respect of allegations of racist and/or discriminatory behaviour" between 2004 and 2021.
The ECB said Ballance, who is currently playing for Zimbabwe in a Test against West Indies, "admitted liability in response to the charge against him for his use of racially discriminatory language".
In August Ballance issued an apology, which Rafiq accepted. Ballance was later released from his Yorkshire contract and returned to play for his native Zimbabwe.
Yorkshire co-chair Lord Patel, who will step down in March, said accepting the charges was "an important step forward" for the county "as part of its journey to learn from the past".
He said: "Since becoming chair it has been clear that we needed to accept and take accountability as a club for the cultural issues which allowed racist and discriminatory behaviour to go unchallenged."
