I do know that stylist will usually have a Big Box of Accessories (or similar) and that accessories will be reused many times.
It could be that Han was given the necklace to wear by a stylist back in 2022, and Seungmin picked it out recently as one that he likes to wear.
But actually all the members's outfits look like something they chose to wear themselves, they don't have a cohesive look as a group while filming this bit.
Han does love to dress up and be extra sometimes, and I can fully imagine him picking out every part of that look himself.