Quote: "Are. We locked in to the VS IDE? It seems like that is all we are using...
Can we use CodeBlock's Ide?"
You're not locked into the IDE, but you are locked into the compiler. AppGameKit for Windows only provides VC++ libs, so you need to be building your game with the VC++ compiler. There is nothing to stop you doing this from another IDE. That said, the only Windows templates provided are those for VS, so you'd have to setup your own project for a different IDE.
Quote: "Is The AGK2 C++ ANSI compliant?"
Yes, at least the API it provides is. There is no C++ ABI though and AppGameKit is closed source, so you're only able to build using the compilers (and compiler settings, and standard library implementations) that are able to link to the binaries provided.
Sorry, don't know about GUI development with AGK. I've never tried. You can link to any additional C++ libraries you like that are supported on the platforms you're targeting, but I don't know how easy it would be to get AppGameKit to play nicely with something else like a GUI library that was also trying to manipulate the window.