What is the significance of congressional medal recipients vernon j. baker and dr. mary edwards walker?

Both were out of the norm for Medal of Honor Recipiants. They both received their medals at a much later date, but for different reasons.

Baker didn't receive his Medal of Honor until many years after WWII, because he was African American. **
Baker was the only African American officer in his company in WWII. He commanded a weapons platoon of two Light Machine Gun (LMG) squads and two Mortar squads. His unit was ordered to assault a German mountain stronghold, called Castle Aghinolfi, at dawn. Though caught under heavy fire with his men by the heavy German defenses, Baker crawled out to safety and personally destroyed a German machine gun nest. He then led his men with their laaLMGs and Mortars to destroy three German machine gun nests, two German observation posts, two bunkers, and German telephone lines. At the end of the assault, only six of the platoon's 25 soldiers survived.  
**It was not until January 13, 1997, that Baker was awarded the Congressional Medal of Honor for his deeds after a 1993 U.S. Army commissioned study found that racial discrimination was evident in awarding of Medals of Honor during WWII.  

Dr Mary Edward's Walker was the only woman to ever receive the Medal of Honor and one of only eight civilians to receive it. She lost it in 1917. She is one of six people to have the award restored to her.
She was the first female surgeon of the Union army. She worked as an unpaid field surgeon near the Union front lines. She frequently crossed battle lines and treated civilians. On April 10, 1864, she was captured by Confederate troops, and arrested as a spy, just after she finished helping a Confederate doctor perform an amputation.  She was sent as a prisoner of war to Richmond, Virginia until released in a prisoner exchange.
After the war, she was approved for the highest United States Armed Forces decoration for bravery, the Medal of Honor, for her efforts during the Civil War.
Her name was DELETED from the Army Medal of Honor Roll in 1917 (along with over 900 others); because she was a woman & civilian. President Carter restored her medal posthumously in 1977.  She is one of six people to regain the award.