Grand Duchess Maria Pavlovna of Russia, known as "Maria Pavlovna the Younger" (In Russian Великая Княгиня Мария Павловна) was the daughter of Grand Duke Paul Alexandrovich of Russia and Princess Alexandra of Greece and Denmark.
Princess Victoria Melita of Saxe-Coburg and Gotha, was the third child and second daughter of Alfred, Duke of Edinburgh and Grand Duchess Maria Alexandrovna of Russia. She was a granddaughter of Queen Victoria as well as of Tsar Alexander II of Russia
From left: King Constantine of Greece, Queen Frederike of Greece and Prince Charles of Engand. I am not sure what this ceremony is for, but I believe it may be a memorial service possibly for Queen Frederike's husband?
Queen Alexandra in her youth years. Maria Feodorovna (Nicholas’ mother) was sister to Queen Alexandra of Great Britain, which explained the striking resemblance between Tsar Nicholas II and King George V. Also looks like pss Alexandra of kent.