Hi, antrock! Welcome to the forums.
While I'll leave your third person questions for someone else, I can answer your question about scripting.
The good news is - YES, AdventureMaker supports scripting. However, the not-so-good news in your case is that it doesn't support C#. Instead, it runs off of Visual Basic Script.
Now, this shouldn't be too bad because I know enough about programming languages to know that VB and C# have many similarities, so you'll almost certainly be able to catch on to VB pretty fast.
VBScript is merely a subset of the Visual Basic language. AdventureMaker provides a nice little reference for looking up the most common scripting actions, objects, and properties. You can also get more information on VBScript and Visual Basic on the
Microsoft Developer Network website
AdventureMaker Documentation and FAQ
Using VBScript, you should be able to make AdventureMaker do just about anything you want...assuming you can figure out how to script it. If you come up with anything really helpful or spectacular, please feel free to post a tutorial or plugin for it.
Again, welcome to AdventureMaker Forums, and hopefully someone will be able to answer your questions about third person games.
-J