Well, your Windows Live login that you used will have a record of your apps you installed, much like your Google login for the Play Store. Your contacts are on whichever account you choose, I keep mine on my Gmail account still, since I switch between my Trophy and other Android device. I also have an unlocked HD7 that I use for travel.
Just like when you were first learning to root Android, you followed the guides step by step. As long as you do the same here, you will be fine. DFT has done some awesome work, and WP7 would prolly not be where it is without them.
If you have your Trophy activated, you can use it as a hotspot, but only with HSPL and a custom rom. I never bothered doing it with my Trophy, but it's definitely an incredible thing to have, especially if you have any wifi devices you carry around.
Need a recovery for your Motorola Cliq 2