Mostly.
You can run your Android apps from the command line using the standard react-native run-android. Then use Deco as your text editor. Hot reloading will work as expected (you will need to enable it in your emulator by shaking the device once your app loads).
For now, Deco only supports running the packager/simulator if you're using iOS. If you want better Android support immediately, please consider contributing a pull request to the Deco IDE repository.
Not yet.
However, Deco is written as a web app (React + Redux) and packaged as a desktop app via Electron. So it shouldn't be too much effort to build for Windows. If you want Windows support immediately, please consider contributing a pull request to the Deco IDE repository.
Yes. However, Deco won't be as useful. Features like running the packager and simulator won't be useful for web React. You will need to run webpack with hot reloading manually in order to have your app hot reload as you work in Deco. Additionally, the default component registry for searching and inserting components is specifically for React Native right now. We're still figuring out how to add custom component registries to the IDE.
Yes. However, Deco won't be as useful. Most features are tailored to React Native, React, and JavaScript. That said, many things (e.g. tweakable properties) could be useful for other frameworks (Angular & Ionic) or even other languages (Ruby, Python, etc). Supporting other frameworks and languages isn't a priority for us, but we welcome pull requests for these things, so long as it doesn't hurt the React Native development experience.
Use the standard react-native Chrome debugger. On iOS, you can open the debugger using the debug menu (⌘+d). We hope to add integrated debugging support to Deco in the future.
We recommend following the Facebook's official getting started documentation, and then going through this guide, React Native Express.