Google Contacts, the address book built into Gmail, lets you keep track of all your contacts, see when you last interacted with them, and more.
Combine project PDFs in manifest order and send the owner a link.
Get PDFs merged in the order you list. The folder owner gets a link in chat. You choose where the finished file goes.
Attach one ordered PDF packet to the project task.
Your reviewer gets a single PDF in the order you set, with the finished packet attached and linked on the project task.