Is it possible to show all items from the sale order in the Picking Ticket even if they are already shipped?

dear god. why would you want to do that? talk about a nightmare for your picking staff.

The idea is to have separate columns for ordered, shipped, to be picked up quantities.

Pretty sure the whole Sales Order record is available to picking ticket template so you can access details from it

salesorder.item

instead of

record.item

IIRC at my previous place I had a custom freemarker function to join the lines based on orderline number