And for foreign royals, what would the predictions?
We know very little but just for fun, my predictions/desires:
Victoria: Connaught Tiara + Pink Topaz Demi-parure.
Mette-Marit: Queen Maud’s Diamond Tiara + rivières and brooch from Sonia + Queen Alexandra’a Necklace earrings.
Mary: Danish Ruby Parure (reduced earrings).
Elisabeth: Vestey Tiara + 18th Bday Necklace or a loaned simple rivière. Earrings from Mathilde. Maybe Fabiola’s Waterfall Brooch.
Catharina-Amalia: Mellerio Ruby Tiara, earrings & brooch + a substantial diamond rivière.
Stephanie (if): Vine Leaf Tiara + big diamond rivière + one diamond rose brooch.
Infanta Elena: Maria Christina Pearl Loop Tiara (why not, even Simoneta has worn it, but am not sure Letizia would lend it easily) + smaller diamond rivière + a brooch from Sofia.
Charlene/Caroline: the Cartier Pearl Drop Tiara (IIRC it belongs to Albert II) + fringe necklace.
Sophie of Liechtenstein: Habsburg Fringe + big floral brooch.
Marie-Chantal: Greek Ruby Parure (on exceptional loan from A-M).
Margarita of Romania: her Greek Key Tiara + her fleur de lys brooch.
Margarita of Bulgaria: nothing.
Katharine of Serbia: her paste tiara.