Kate has to dress classically- her clothing needs to withstand the test of time in photos and footage. The most ridiculous pics of Diana are the ones where she's dressed bang on trend- it dates dreadfully.
Philip and Michael are fascinating examples of Victoria's conquer by marriage policy with her DC, too. Philip is related to the Queen via Queen Vic because he is a descendant of her Dd Princess Alice of the United Kingdom, and Elizabeth is obviously a descendant of her DS- Prince Albert Edward King Edward VII. Philip is related to the last Tsarina Alexandra by being a descendant of Princess Alice of the United Kingdom. Alexandra was her daughter and the sister of Philip's Maternal granny, Princess Victoria. He is also related to the Tsar via his Paternal DGM, Russian Grand Duchess Olga (not the one who was murdered). So he is related to both Nicky and Alix, independently of each other, and to their DC.
The Queen herself will be more distantly related to Alix via Queen Victoria and to the Romanov DC via the Victoria link and by being a descendant of Alexandra, Queen Consort of Edward VII and sister to Princess Dagmar of Denmark, mother of the Tsar. I think she's too tenuous/wrong lines to be useful for verifying the Romanovs, although Philip, I think Charles & Michael of Kent were used due to closer genetic links. When Philip married the Queen he also didn't have to "become" a British citizen the bureaucratic way; due to his descent from Victoria he was already entitled to be one!
Prince Michael (who has cultivated both interests and relationships with Russia and a Tsar-alike beard) is vaguely related to Tsarina Alexandra due to his descent through King Edward son of Victoria and brother of Alice. He's then related to Nicky distantly through Edwards Queen - Alexandra, sister of Dagmar who is mother of Nicholas. He's then related to Nicky more closely via his maternal grandparents, who were members of the Greek Royal Family (which is related to the Danish one so another Queen Alex & Dagmar link) and the Russian royal family. As a grandson of noted Tsar-alike George V (a cousin of the Tsar via parents Edward & Alex) it's unsurprising that he looks weirdly alike them both. His head on the RAC insignia stuff is very Tsar-y.
If you study Victoria's DC, you realise how many Euro royals are descended from her and how dangerous she was as a passer of haemophilia. She introduced it to Russia via Tsarina Alexandra and to Spain via Princess Victoria Eugenie (Ena) of Battenberg, her DGD via Princess Beatrice. Ena married the heir to the Spanish throne and had haemophiliac sons. The Spanish royals considered her a curse on the house of Bourbon-Palma and she had quite a sad marriage. The Romanov daughters, whilst not affected by Haemophilia, were strongly suspected carriers because certainly a couple of them would bleed profusely with any cut or scrape. One of them- Maria I think, bled so much having her tonsils out that Alexandra had to bully the surgeon into finishing, he thought he'd kill her.