I don't think it is that easy with MS Office. There are more places besides the App folder, like library/Application support, Frameworks etc.
And i am pretty sure they tied the unique hardware id to the installation. Well you can find solutions in the web i guess.
That’s a good idea too. However, I’m keeping my (late) 2010 machine in service. It has High Sierra and can’t be upgraded to Mojave. The 2012 machine came loaded with Mojave, which will able to be upgraded to Catalina this fall.
It is unimportant what version of macOS it runs. Clone your old partition to that new drive and you are done.
All macOS upgrades are free. No need to preserve a preinstalled macOS.