Yes, the robes denote different orders
Order of Garter - Prince William, Prince Edward, Duke of Kent and Duke of Gloucester
Royal Victorian Order - Princess Catherine, Duchess of Edinburgh, Duchess of Gloucester
I don't know the one Princess Anne was wearing.
I read that Princess Anne was wearing her Royal Naval uniform but also an official robe as her pivotal role in Saturday’s coronation, she was acting as the Gold-Stick-in-Waiting during the King and Queen’s procession from Westminster Abbey to Buckingham Palace following the coronation.
In that role, Anne was seen on horseback leading 6,000 members of the Armed Forces from the abbey to the Palace in the largest procession since Queen Elizabeth II’s coronation seven decades ago.
She was quite hidden on the balcony though
Apart from her lovely red plume, the Gold Stick in Waiting could have been v useful!