I am certainly no computer expert. That is why a lot of this falls under question A, in my first post. Is it possible? Bill2, I'll take the second part of your post first. My thinking may be all wrong, but I was thinking of it like you were installing a new drive C: You take the empty hard drive and install Windows 7 Home Premium(HP). Then you take a back-up made previously, and restore only the programs (and their serial numbers) along with the data, but you don't restore any part of the operating system, since it would probably make a very unstable OS. So an "in-place" installation, wasn't what I meant. Sorry if I gave that impression.
As to the comparison of Windows 7 editions, there are several "features the child needs", that I think are in Ultimate but not HP. By child, I mean a kid about to enter college. No matter how old they get, they will always be the kids to me. I have one "kid" who is into graphics and video. He wants to work on content for DreamScene. At the Microsoft site, they say "Windows DreamScene is a Windows Ultimate Extra." I think I have seen where it can be run on other incarnations of Windows, but it is only with Ultimate that it is supported natively.
About Windows DreamScene
From what I've read, I don't think his dreams of all his old XP games working in XP mode is realistic, but he does have an old graphic tablet with no Windows 7 driver, that we were able to get working on my Ultimate installation in XP mode.