Can the platform (with apps) be transplanted to other location(s) on the same, or other drive(s) ?

To your second point, yes, you can simply copy it around as you like from drive to drive. From folder to folder some rare apps may break though, and you should copy and test each individual app to make sure it works if you are changing the path other than just the drive letter.

To your first point, it largely depends upon which apps you are running. If you are running portable OpenOffice or LibreOffice, they will more than likely break when installed a few levels down depending upon the length of the folder names. Other apps will also misbehave when installed as such, but there is no definitive list of what will and won't, thus the recommendation for root level installation.

These apps have a limitation in the apps themselves due to the sheer depths of sub-directories within them (and the resulting overall length of the path) that causes them to crash when installed more than a couple levels deep of a dozen characters each. Other than that, most apps should be fine with it. Of course, Program Files is not supported and apps will not install or work from there.

Note: Installing somewhere else and moving the apps will not alleviate this. This is an issue within the apps themselves.