You can pre-sign once it is shipped. You will have to print out the pre sig paper and make sure it's visible on the front door... Leaving instructions for the fed ex driver..
AFTER the first delivery attempt, you can go to the FedEx hub after a certin time and pick it up there.
If you arrange and leave a signed release at the door they might be able to leave it at the door. I think that the seller can say no way and a direct signature must be obtained.
For everything I've ordered from Apple, there was a link on the order status page that took you to a form you could print, fill in, sign and hang near where packages are usually delivered that allowed FedEx to simply leave the package.