I found the right Diana-inspired hair, earrings, and tiara so I thought I'd give it a go. Needs a bit more work, I know, but I'll probably fix that later. : r/thesims
The Sims Resource - Tiara Snow Queen
BEO CREATIONS: Diamond tiara
Princess Crown by simgamelover12 - The Exchange - Community - The Sims 3
Travez tiara at Jomsims Creations - The Sims 4 Catalog