Well actually are still a good guy (as in trying to save the galaxy) when you are renegade. It's more like a choise between being the ultimate dick (renegade) or a wussy (paragon).
Who says she is? Maybe you can still cut the limbs of immortall people. Probably not, but that would damn cool. I always hate when things automaticly die in games if they lose a limb.
Probably a nerfed char. Game developers seem to do that when they are doing a demo or something. It would be a bit embarassing if the dev playing the game would die.
The robo horse probably would be just a easter egg that is refering to Oblivions horrible horse travel. Well they can't seriously create a fucking robot horse can they?