Mrs McConville, a widowed mother-of-10, was one of the Disappeared.
She was taken from her flat by the IRA, murdered and secretly buried. Her body was found 35 years later at a beach in County Louth.
Reports on the the arrested women, aged 57 and 60, will be sent to the Public Prosecution Service.
Another 57-year-old woman, arrested on Wednesday, was also later released pending a report to the PPS.
Earlier this month, a 57-year-old woman and a 56-year-old man, arrested separately in west Belfast were both released after questioning.
The man was released without charge and police are preparing a report on the woman for assessment by the PPS.
Last month, Ivor Bell, 77, a leader in the Provisional IRA in the 1970s, was charged in connection with the murder.
He has been charged with aiding and abetting murder and membership of the IRA.
Mrs McConville, 37, was kidnapped in front of her children after being wrongly accused of being an informer.
The claim that she was an informer was dismissed after an official investigation by the Northern Ireland Police Ombudsman
She was held at one or more houses before being shot and buried in secret.
The Disappeared are those who were abducted, murdered and secretly buried by republicans during the Troubles.
The IRA admitted in 1999 that it murdered and buried at secret locations nine of the Disappeared.
The Independent Commission for the Location of Victims' Remains was established in 1999 by a treaty between the British and Irish governments.
It lists 16 people as "disappeared". Despite extensive searches, the remains of seven of them have not been found.
Two more women arrested by detectives investigating the 1972 abduction and murder of Belfast woman Jean McConville have been released.