Thanks for the assurance, Dave.
In fact, I tried it. I unplugged the USB connected Seagate Free Agent hard drive (on which I had performed a full bootable backup operation with my iMac) from my iMac and plugged it into my wife's Mac-mini, a much slower and less capable machine.
The little Mac-mini booted to the external hard drive, albeit slowly, and the user interface and program content appeared identical to that on my iMac.
In an admittedly limited experiment, I exercised four programs from my iMac on the Mac-mini and found that they all operated properly. In fact, I was able to bring up my TurboTax/Windows program that had been running on the iMac under Fusion 1.1 and Windows XP. TurboTax/Win functioned normally on the Mac-mini.
I did observe two anomalies, neither of which was a real issue:
1. When I attempted to play a song in iTunes, the program required that I agree to the Apple license for iTunes before it would launch; although I had long-since done so on my iTunes program on the iMac. When I acknowledge the license terms, the program launched and played normally.
2. When I launched Fusion 1.1 the program requested that I identify the location of the virtual machine, something it had never done on the iMac. When I clicked on the appropriate box, it found the VM and ran Windows XP normally.
All-in-all a very successful experiment.
I am impressed.