Working through this with us?
Your launch date is fixed. Everything else is counted backward from it. Put in your lead times and get the week you have to order by... before the calendar decides it for you.
Packaging goes first because your manufacturer cannot fill, seal or label anything until the printed packaging is in their building. If one company makes both the product and the packaging, set packaging to 0 and put their full lead time under production.
Production starts when the deposit clears and every part has arrived, not when you send the order. Ask for lead time in writing and ask what it assumes.
Freight is door to door. Overseas orders also sit in customs, which is part of why the ranges are wide.
The buffer is not optional. Something is late on almost every first run. The buffer is what keeps a late proof from becoming a late launch.
What this does not include: the time to finish your artwork, get the agreement signed, or have samples approved. All of that has to be done before the order-by date, not after.
Working out what the run costs? Start with The Launch Cost Stack. Still comparing manufacturers? Use The Quote Comparer.