Leon Goldstein had empty cigarette cartons, used by cigarette makers to package their hand rolled products. There were cigarette makers in the cottages in the passageway, awake at the time of the murder and discovery. I believe Leon intended to deliver his empty cartons to the men who waited for him in the cottages, but was probably waived on past as he looked into the yard, by gathering members crowding around Stride.
Interesting possibility, but it relies on Louis arriving before Leon. Yet Fanny says she saw Goldstein walk by, and only afterwards heard Diemschutz's cart go by.