encrypted /tmp? encrypted home dir but remotely rebootable?

[Bob Smith]

I've worked out how to set up encrypted swap and /home/bob on my
laptop, but is it possible to set up encrypted /tmp too? If so,
how big does the /tmp partition need to be?

Also, I want to make my home computer remotely rebootable but
with some encrypted stuff: swap, /tmp (if possible), and
/home/bob. Has anyone set a computer up so that it can rebooted
without having someone sitting at the keyboard to type in the
passphrase, but so you can ssh to it later and mount your own
home directory? Or maybe I need to have two userids for this,
bob1 who has access to sudo cryptsetup to mount /home/bob, then
log out and back in again as bob?

Thanks for any tips.