I don't do anything when I shut down my Mac Pro. I just hit shut down.
Still running the same system install (with the upgrades on top, obviously) since 2008.
Auto updates and date and time won't save you any CPU. Those are normally run once a day, and they only take a few seconds.
Spotlight? Eh. You have a Mac Pro. Pretty sure you can handle Spotlight in the background. 😛 It only does things when you save anyway.
I would just leave everything alone. This isn't a PC, you don't have to hold it's hand. Macs can pretty much handle themselves.