forestcovered fits all your requirements! We're slow-to-medium paced and very backtag and slow tag friendly, and we welcome new players. We don't have any castmates for your characters, but we'd love to have you here!

Forest Covered is a slice-of-life-with-plot-elements game loosely based on Spirited Away. Characters sign a contract to work on a resort island for spirits in exchange for having a wish of theirs granted. Upon arrival they lose their memory of their names, which are replaced by work names, but their names can be regained later.