Mary wore the half-up hairstyle sometimes when she was younger, but more often put her hair in a bun (which Kate rarely does), a pony tail, or straight down. But Kate often wears the half-up. So we see Mary doing it more now. It's too severe for her aging face.
And here Mary does the Kate thing with her hands. Kate doesn't get that she could hang her hands at her sides so she does this girly, demure "I'm holding a clutch purse" with her hands even though she isn't. And Mary copied it as soon as Kate became royal.
I think Princess Victoria also tries the half-up and half-down hair, and Sophie Wessex in these past days. I don't like it on any of the ladies (and I include Kate/Catherine).
The hand thing - Letizia does this also and I have been thinking that it is because of Covid and keeping hands visible and occupied or something.
But is she copying Kate? I mean, those dresses are all over the stores, her hair style can be seen everywhere and this half-up half down has been around for centurys and is certainly not an invention of Kate. All the royal ladies do wear similar styles: the royals in the same clothes thread has examples of Letizia and Kate, Mary and Viccan, and all of them in mixed combinations.
Perhaps they are sometimes inspired a bit, like "she had her hair like that and it looked nice, let's try it too", but I do not really believe there is any SWFing.
And now back under my rock....