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 - S-Club LL ts4 Hair Accessories 202010
UliKa Tiara RC - The Sims 4 Catalog
Wind Tiara Conversion at My Stuff via Sims 4 Updates | Sims 4, Sims, Sims 4 toddler
Swan crown, hope you like, thank you. Found in TSR Category 'Sims 4 Female Hats' | Sims 4, Sims, Sims 4 tsr