Can all Mac software update with one click?
No - there is no combined update process that works for all conceivable let alone all existing (or even popular) software.

But you can automate the Apple updates and use a third party app to automate the Mac App Store updates.


Can Mac App Store installs &amp; upgrades be automated?


That way two pieces of automation can be chained together to meet your goals.

Diving deeper, there are all sorts of MDM / endpoint management suites like Munki and commercial ones like JAMF Pro that set up a framwork to automate this at scale remotely for an out of the box management toolchain when combined with Apple DEP.

You could go the managed route and have a script that pushes out updates for you like a school lab or corporation might choose to do.

One of the reasons why Apple has said it introduced the App Store model to OS X is to combat this level of complexity for many users - especially for those new to Mac. For apps that are distributed from the App Store and supplied as Apple products, there is in fact a one click Update button that works for both OS updates and App Store updates.

In your case, MS Office is not included in this easy deployment scenario (yet and perhaps ever) so the ease of updating App Store apps won't help you.