Well, the screenshot that was leaked of Verizon's inventory system, showing the Nokia "822", is assumed to be a "version" of the 820. What it means, who knows? As far as bloatware goes, there's not much they can do with Windows Phone that we as users can't undo. The Verizon app on the Trophy is just as easy to uninstall as any other app. Tap/hold, Uninstall. Yes, it is that simple. Thank you, Microsoft. They can't load it up with bloatware, because the OS is locked down in such a way that it wouldn't matter if they did. I'm a developer, so I understand how it works a lot better than the average user, but let me see if I can explain it...
For one thing, there is no multitasking. None. You don't see task managers in Marketplace like you do with Android because there is no need for one. Tasks can't run at the same time, so they can't run your battery dead by running amok in the background. Only one app can run at a time, and when the phone locks, the app in the foreground stops unless it is allowed to run behind the lock screen, and the user has to allow that - if it tries to run behind the lock screen and doesn't get your permission (and give you a way to prevent it in settings as well), it will fail certification and won't get into Marketplace Windows Phone Store.
I guess the next big thing is that it is so simple to uninstall apps. Go to the app list (not the home screen), and tap/hold and uninstall. It really is that simple, and then it is gone. Completely.
As for the security model of Windows Phone, apps are not allowed to access the data that is saved in the phone by other apps. That data is "sandboxed" - isolated - from all other apps. If I write one app that saves your credit card information, even I cannot write another app that gets that credit card information that was saved by the first app. This applies to all data in the phone. The exception is if the data is saved in the cloud. If my app saves data in the cloud, then any app that I allow access to that data can have access. Be sure you know where your data is going when you save sensitive data.
To your question about a "version" of the phone being a dumbed down version of the hardware? I would not expect that, but I also can't rule it out. Let's put it this way. If you were Verizon, would you want your "922" (just assuming for a moment that's what they brand it with) to be under-powered compared to ATT's 920? Will that sell phones? I didn't think so..... Let's hope the people making decisions at Verizon are as smart as those of us buying phones from them. 
