I have been seeing some vintage footage of the royal wedding in Oslo and I know Sonja wore a standard bridal headpiece probably of beads, silk flowers, and wire. But did the royal ladies who attended wear their tiaras and orders? or was it a daywear event with hats and pearls?

No tio was an afternoon Wedding with white tie dress code
Queen Ingrid wore the pearl poiree Set
then Princess margrethe the bvaden palmette tiara with her sapphires
Princess Ranghild the pearl cirlce tiara
Princess Astrid the Vasa tiara

Also attending the wedding were Princess Margaretha of Denmark (née of Sweden) with her two sons and daughter-in-laws. The Princess wore her Floral tiara, while Princess Anne (wife of Prince Georg) wore a Diamond tiara and Countess Ruth wore the Opal tiara.
The Grand Ducal couple represented Luxembourg and Grand Duchess Josephine-Charlotte wore the Emerald Peacock tiara.

On the eve of the wedding the Government also gave a white-tie dinner at Akershus Castle / Fortress where more tiaras were on display.

The wedding was supposed to have been even grander with a ball at the Royal Palace on the 27th and with representation from the United Kingdom. However, the ball was cancelled due to the Soviet Union invasion of Czechoslovakia and on the 28th the news of the death of the Duchess of Kent the day before reached Oslo. So no representative from the United Kingdom.