Missing Items From The Store Menu?

Hi all.. I've recently built up enough of a donut pile to start buying premium characters and buildings. I've been scrolling through the menus to find the things I've wanted for a while (Dr. Nick, Arnie Pye, most of the Squidport performers/buildings & lots more), but I can't find them anywhere?? I've tried to find out where they have gone & the only thing I can think of is the vault? ..is it just a case of waiting for them to appear week after week? :/