The family members, who have been feuding for years with the people Parks appointed to handle her affairs, filed the legal challenge Friday.
"We still are very open to talk settlement in this case, if for no other reason than both sides have a deep respect for Ms. Parks," Frederick Toca Jr., an attorney for the family members, said Monday.
A pretrial conference is set for May 9 before a probate judge.
Parks' family members have said they started legal proceedings in December to protect her legacy. They are fighting for control of the rights to Parks' name, photos and other yet-to-be-determined intellectual property.
In the complaint filed Friday, the family members allege that Parks' longtime friend Elaine Steele, who handled her affairs, exerted undue influence over Parks.
Parks was subjected to threats, misrepresentations and coercion, the family members allege in the complaint. Parks was suffering from a mental condition that caused her to not understand her estate and assets at the time the will was dated in 1998, they say.
Parks' relatives have complained that the sale of extra copies of the obituary programs from her funeral cheapened her name.
But a former attorney for Parks has said the proceeds only covered costs, plus a small profit that went to the Rosa & Raymond Parks Institute for Self Development, a Detroit-based organization founded by Parks to teach young people leadership and character development.
Parks' relatives, all sons and daughters of Parks' brother, Sylvester, have said it's one more example of how Steele and retired Detroit Judge Adam Shakoor have misused their aunt's name since she gave them control of her affairs, about the same time she began suffering from dementia.
Parks died in October at age 92 in Detroit, where she had lived since 1957.