Barbara, thank you for your compilation of Orders.
Here is a bit of information to fill in the gaps - I hope.
The Maltese Cross item worn by the Duke of Edinburgh is the Royal Victorian Chain which although similar in name is different from the Royal Victorian Order. He received this from HM in 2007.
The Maltese cross item worn by the Price of Wales is different. His is the badge of the Knight Grand Cross of the Most Honourable Order of the Bath (military division).
The PofW and the DofE also wear their insignia of the Order of Merit which is the red cross on a red and blue ribbon. The DofE wears his at his neck and the PofW wears his with his aigulettes.