Can all Mac software update with one click?
Solution 1:
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 & 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.
Solution 2:
In a word, no.
Different software is installed by different methods, depending on where you bought it from, who wrote it, how old it is and numerous other variables.
Apple tried their best to get a handle on this through the Mac App Store, which allows you to simultaneously update any app purchased through it, and the OS with a single update click, but not all apps are available on the App Store, because they are too old, are simply not offered by their respective developers, or perhaps they offer functionality that is banned from appearing in the App Store, or break it's rules on Sandboxing etc such that they are not allowed.
Macupdate offers an update utility that tries to keep track of updates and pull them down for you, but it can only support the apps that it is allowed to support, and as such is in the same boat at the App Store etc.
Some apps simply run an update check upon startup (check preferences per app) to see if a new version is available, others write in their own update tools, others use 3rd party distribution and update tools like Sparkle to do it for them etc.
In short, on OS X, it's a free for all. There is no way to combine or encapsulate all software updates in a single method.
Solution 3:
The closest thing I have found is the MacUpdate Desktop utility. It does not handle every application, but it handles most of them. The program to do the updating is free, but the service it consults to know what apps need updating is a paid program.